Home

OMEGA2000 User's Manual - Max-Planck

1. 14 S ias no sirae sie san Ne ee ee 15 Sl OS IRON een 15 3 2 Backbrouncd SUD EAC TI OD une ee eier 15 6 Image ca Dra UON ea ea 17 6 1 Focussing the telescope onto the detector 17 CZEFIACIE orbi E RC 17 0 2 doc S lID zee deutet wk eier ld R ET OM 18 0 22 DOM Thi u TRA W AE haies Dept AR A AJ 18 DOS DOC UBL ee dad odo ATE 18 64 Bau pixel qnas umaq aaa ua huwa eisernen 18 NM Eine tiey T 18 6 6 ASTOME IC Calibration uns ed AAA AOL YA 19 6 7 Phiotomettic CaltDEaL OE uenerit ee 19 T CONTE CG A OO ee ee rer 20 DEI ere 20 7 1 1 Read out modi implemented for OMEGA2000 21 722 OPIC aa eet A ODA NAA AAA 26 Til ee O O umapi O Iu O O EE E EA 26 T il MERE TUE OR A O O 26 WIDE ERN 1 7 0 Redd Oute LECH OMICS ee ee 28 Tele GOMTO Ke eroe EI ee T EE 29 S he 3 OMCIESCODC cuoi nota dni USES Rd woj RNA us O ws PGA 30 9 Ehe praphieal user mterface GUM us cust NA aqha OE Seed aes 31 2 1 Loge loch Setti re 31 O Za SATE Dje sjekire an noid Oo dnia d w 32 O Ihe AWTS WA OWS use Re 34 9 3 1 Camera control WI J W sn a s hti e dc add 34 0 52 Realsiim eDispu uuu au ua O WE Initia noo 38 9 35 Telescope control WINdOW are 40 9 944 SAO Map MEDICO NE nea este ia ae AGO Oe 41 232 AI MASS N TINO WER ee Eo ee oda 42 9 3 0 25 tp C hart WIRJOW en O AAA Q A O A 42 AA NE MIDORI zo uyu
2. Astrometry 5h 13 21 13 16 13 11 c O LLI Q 13 06 13 01 12 96 4 824 4 819 4 814 4 809 RA h F r F a a i 7 gt LE 1 E E u w 4 ne L T p 3 j i z LJ z 1 u i a A t m F i a gt o dira T by i a ME 5 i F T 1 LH u E 8 a E is Xu u u BASE P i E P m E u AR P E T J a U Mi z 1 P E a Ai E E i F zu E r 1 a E M pra oo n F a Ee 72 Figure 59 Astrometry field at RA Sh finding chart for astrometric stars from M2000 Astrometry 9h M67 11 94 11 89 11 84 LLI Q 11 79 11 74 11 69 8 847 E ru I x A Er 3 a E m e a i T Ar LJ a a a U da m Vos mu gt T a T E E a zm i 5 P a a F m ji LJ eee o u Eo i a Q2 I a u rg a LJ ag P n F T x a a b e F k tag Le f sxs an TWE B a z E F a E v A e det Fa x i T7 de AT x i E A b 4 EL a a a E E a a iB T a n l 3 U cu 4 2 TM dal Ard a ad a a o ie WB i a tat i g i ee r a r a T F ON m a IE a 5 m im P U gt U E z F F I E m r T E n 7 A a
3. 35 Figure 38 Save options WINdOW cccssssssesseseeseeseeseeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 36 Dieure 39 Realtime display noe eim se CAGE O WE een 38 Figirc40 Telescope Control WING OW ea A i G Q Gada 40 Figure 41 Standard dither pattern with 20 positions for Integer pixel offset red and it cHofal prxeloHsets DIU ae 67 Figure 42 Offsets for the repetition patter ccccccscsscsssssessoecssereesececadeccnennndacssesseosssereseseecs 67 OMEGA2000 manual doc Figure 43 Telescope positions for a complete cycle of 400 independent dither positions Basic pattern 1S SHOW 1 PINK nn oe me e ac n namen are 68 Figure 44 Sky positions for observations of extended obJects 72 Figure 45 Pipeline result for a sparsely populated fteld 88 Figure 46 Pipeline result for an image of an extended obgJect 89 Figure 47 Transmission curves for brad band filters 91 Figure 48 Transmission curves for narrow band fllters 91 Figure 49 The GUI of the DA Tspooler Currently only one drive is supported 95 Figure 50 Eocus Held at RAS T Re u uy t Out e Rv bu a M tur ples dob AO 126 Figure 51 Focus field at RA
4. time Figure 6 Detector readout voltage as a function of time OMEGA2000 supports a number of detector readout modes suitable for various observing situations These modes appear under the lt Readout gt menu and can be invoked with the ctype instruction from the command line interface and from macro files Their detailed properties beyond the general principles described here will be presented in Section 7 1 1 3 2 1 Reset read read Figure 7 Read out mode reset read This is the simplest readout scheme The pixels are reset and read out once at the end of the integration This does not remove the variable pedestal level KTC noise and any initial off sets which can vary from pixel to pixel We do not recommend using this mode for observa tion Its main usefulness is in checking the signal level for saturation 3 2 2 Reset read read double correlated read reads Figure 8 Read out mode Double correlated read Also known as Double Correlated Sampling this is the most commonly used mode for gen eral observing The array is read immediately after the initial reset and before the final reset at the end of the integration This eliminates the KTC noise and other offsets but increases the The variability is caused by a quantum noise source called kTC noise the thermally induced fluctuations of voltage on a capacitance C at temperature T read noise by 42 because the noise from two readouts goes into a s
5. 24 Figure 26 Centre to corner image distortion of the OMEGA2000 optics 26 Figure 27 Working principle of the movable warm baffle With only a cold baffle top rays from outside the primary reach the detector These may be blocked by the movable BARI al AR Od ATR cames MUS 26 Figure 28 The two warm batflles 27 Figure 29 Movable baffle measurement Histogram of the SNR ratios with and without the movable baffle Left Patel Kenter Rieht panel Ka 2 Figure 30 Block diagram of the read out electrontcs 28 Figure 31 Monitoring the dewar temperatures during cool down sss 29 Figure 32 Control panels on the display after login as user o2k 3l Figure 33 The available screens to operate OMEGA2000 3l Figure 34 Welcome screen of GEIRS to start the Instrument 22 Figure 35 Desktop to operate OMEGA2000 with the camera control the online display and lC Tes arie 33 Figure 36 The camera control window with its drop down menus 34 Figure 37 Monitoring temperatures and pressure of the dewar
6. 22h 30 oo 20 E w w o 10 amp 4 gd 0 3 18 00 19 00 20 00 21 00 22 00 23 00 00 00 01 00 02 00 03 00 04 00 05 00 06 00 _ UT moon April Elevation of fields M67 Focus 1h 90 80 NGC 1647 70 Focus iji 12h Focus 50 17h Focus 40 22h 30 eal 20 Eoo nh 9 10 GER 0 20 00 21 00 22 00 23 00 00 00 01 00 02 00 03 00 04 00 05 00 _ UT moon Figure 56 Elevation plots for focus fields January and April July Elevation of fields M67 Focus 1h 90 80 NGC 1647 T v ug Focus p 60 12h Le Focus Dur e 17h i Focus 40 j 22h p 30 e 20 er e ma Ba red ge 10 m 0 21 00 22 00 23 00 00 00 01 00 02 00 03 00 _ UT moon October Elevation of fields M67 Focus 1h 90 80 NGC 1647 m d Focus ve 60 w 12h Focus 50 17h Focus 40 22h 30 d i amp k 10 b O 0 C 19 00 20 00 21 00 22 00 23 00 00 00 01 00 02 00 03 00 04 00 05 00 _ UT o moon Figure 57 Elevation plots for focus fields July and October OMEGA2000 manual doc Appendix 8 Astrometric fields Astrometric data are provided to enable an easy check of the plate scale and a direct determi nation of the image rotation
7. FSO1 FS02 FS03 FS04 FS05 FS06 FS07 FSos FSo9 FS10 FS11 FS12 FS13 FS14 FS15 FS16 FS17 FS18 FS19 FS20 FS21 FS33 FS23 FS243 FS25 FS26 FS27 FS28 FS35 FS34 FS29 FS30 FS31 FS32 UKIRT Faint IR Standard Stars G158 100 SA92 342 Feige 1 5A93 317 Feige 16 Feige 22 5494 242 5494 251 5494 102 GD50 5496 83 GD71 SA97 249 Rubin 149 M67 I 48 M67 IV 8 M67 IV 27 SA100 280 1162 66 163 50 GD140 GD153 M3 193 SA106 1024 5A107 1006 SA108 475 M13 A14 SA109 71 G21 15 EG141 193 48 SA114 750 GD246 Feige 108 Too bright for O Current ID not positive Variable star 1950 00 31 22 7 00 52 36 0 01 01 46 6 01 52 03 7 01 52 04 7 02 27 39 2 02 54 47 2 02 55 12 9 02 55 38 8 03 46 17 4 04 50 25 4 05 49 34 8 05 54 33 8 07 21 41 2 08 48 21 9 08 48 31 0 08 48 39 4 08 51 02 1 10 31 14 5 11 05 27 6 11 34 27 6 12 54 35 1 13 39 25 7 14 37 33 3 15 35 59 9 16 34 26 3 16 38 54 2 17 41 32 5 18 24 44 5 20 39 41 9 21 49 53 0 22 39 11 3 23 09 50 4 23 13 38 2 01950 12 24 29 00 26 58 03 97 34 00 28 20 07 00 47 05 02 34 00 06 39 00 04 04 00 58 54 01 07 38 00 19 34 15 52 37 00 00 53 00 27 10 11 55 02 12 00 36 12 03 26 00 25 14 11 26 08 04 53 04 30 04 35 22 18 08 28 44 59 00 14 36 00 24 03 00 28 39 36 26 56 00 23 44 04 01 17 20 15 21 02 09 16 00 56 55 10 30 46 2 06 58 0 46 DG K o 2
8. action LDLacLtron flag Graphics Output Two integers that specify the action taken and the feedback to the user action flag 0 gt all actions carried out image taking analysis best focus ad justment 1 gt do only image analysis no instrument and telescope commands sent 2 analyze images and adjust focus to the best setting 3 take images and analyze graphics output 0 gt show only final graph 1 gt show all graphs including the selection process objects Approximate number of objects to be searched for and analyzed The default value of 40 is appropriate for fields with enough stars For sparse fields the parameter may be set to lower values P8 boxsize Total boxsize in arcseconds around objects for the objects analysis The default value should be working In most cases Internal The routine contains three internal parameters which are defined at the beginning of the rou tine Pixel saturation Maximum count level per single image exposure in the linear detector regime Minimum and maximum galaxy cutoff parameters The empirical FWHM cutoff parame ters for the final object selection step Trouble shooting In case you experience problems no objects found and do not want to rely on the focus off sets you have to evaluate the focus test manually Proceed as follows Flatfield the focus exposures select one object not saturated 1f possible in the optimum focus image Use center gauss to measure its h
9. 5 sum 5 0 1 n average action flag sum save flag Use 5 images for the sum reference frame determination do single image reduction summation write out only final sum frame kappa sum 10 eliminate all cosmics that are above a 10 sigma cutoff cuts 2 5 set cuts of reduced images to median 2 sigma median 5 sigma flags 0 1 1 save position screen _ output do not save sky frames do full detector calibration at start display screen output flatfield std cal file use the standard calibration ASCII file to look for the relevant calibration frames Examples o2k online standard pipeline online mode No parameters needed The function has to be called after the observations have started The image catalog created by the observing utility 1s used The sky is determined from 5 frames with the fast median mode The superimposed images are written to disk after every Je image The kappa_sum cosmics clipping parameter 1s set to 10 OMEGA2000 manual doc o2k pipeline june10 obs 3 2 5 5 0 1 10 2 5 0 1 0 amp disk a o2k cal file cal Reduce the image catalogue junelO obs cat Use 3 images on either side 1 e a total of 7 images for the sky determination in outlier mode 72 with outlier clipping 5 sigma above the median level Use 5 1mages for the refer ence sum frame do reduction and summation and save only the final master sum frame Remove cosmics that are above a 10 sigma threshold The cuts for the final
10. 2 5463 geographic long HIERARCH CAHA TEL DOME AZ 145 90 dome azimut degr HIERARCH CAHA TEL DOME EL LOW E 57 33 dome door low lim HIERARCH CAHA TEL DOME EL UPP E 76 95 dome door upper lim NIERARCH CARA TEL FOCU ID PRIM ID of used focus HIERARCH CAHA TEL MIRR S1 COLLAREA 9 09 eff coll area of S1 m 2 HIERARCH CAHA TEL FOCU F RATIO 3 48 f ratio HIERARCH CAHA TEL FOCU LEN 12 195 focal length m HIERARCH CAHA TEL FOCU SCALE 0 1690 focus scale mm arcsec HIERARCH CAHA TEL FOCU VALUE 30 718 focus rel setting HIERARCH CAHA TEL POS AZ START 143 60 telescope azimuth at start HIERARCH CAHA TEL POS EL START 63 70 telescope elevation at start HIERARCH CAHA TEL POS HA START 21 079635 fF 0l 51220 9 DR deg HIERARCH CAHA TEL TRACK STATUS NORMAL tracking status HIERARCH CAHA TEL MIRR S1 TEMP 124 7 Z Sl temperature HIERARCH CAHA TEL TEMP1 13 3 temp frontring HIERARCH CAHA TEL TEMP2 12 8 temp dome HIERARCH CAHA TEL TEMP3 9 5 temp central body HIERARCH CAHA TEL BAFF POS IN of baffle pos in out HIERARCH CAHA GEN AMBI WIND SPEED 0 5 wind speed m s HIERARCH CAHA GEN AMBI WIND DIR 36 wind dir deg HIERARCH CAHA GEN AMBI RHUM 88 relative humidity HIERARCH CAHA GEN AMBI PRES 784 5 air pressure HIERARCH CAHA GEN AMBI TEMP 10 9 air temperature Celsius HIERARCH CAHA GEN AMBI FWHM 1 9 seeing arcsec HIERARCH CAHA GEN AMBI EXTINC 15 extinction
11. DATeof dev Writes an EOF end of file to tape DATeom dev Positions the tape after the last file end of medium DATfsf dev nfiles Skip forward by nfiles files marks DATrew dev Rewind the tape DATtst dev Read tape status DATunl dev Eject the tape FitsList dev nfiles firstfile QueueFiles path file fits oder newdata sav QueueControl StartTapeSpooler datSpooler csh datSpooler 0 datSpooler 1 datSpoolerKillDisplay csh OMEGA2000 manual doc Appendix 5 FITS keywords written by OMEGA2000 In red are corrections to the keywords as of July 2003 SIMPLE T BITPIX 16 NAXIS 2 NAXIS1 2048 NAXIS2 2048 oa BSCALE 10 BZERO 14368 000000 real bzero bscale value BUNIT DU PIXEL CTYPEl1 PIXEL CRPIX1 1 0 CRVAL1 ZLU CDELTI 150 CIYPEZ TPIXEL ERPIX2 1 0 CRVALZ 1 0 CDELTZ L0 COMMEN TOA pb Soe pa DATE UILOTS 220035 UT date creation of file DATE OBS TILADIZO0D0S UT date of observation MJD OBS JD 2400000 5 Start Integration UT 83832 23 1T7 12 universal time EOread EST 4632 01 17 12 local sideral time EOread DIES IST NICHT LST ORIGIN 4 He3 Centro Astronomica Hispano Aleman OBSERVER master TELESCOP CA 3 5m FRATIO riss E add TELLONG 2 546250 degrees TELLAT 37 222361 degrees TELALI 2168 000000 meters Soe be pb COBMBIBRA EOMP COMMEN COA bp ONE INSTRUME unenewn OMEGA2000 Y Y Y Y PIXS
12. If FLAT is present the specified frame used as flatfield i e l FLAT has priority over JXIBIBER I NOTE The filter names have to be identical to the specification in the descriptor FILTER I The identifier is followed by and the calibration file name with l Bach ENLOTMaCEOM The names including path should not exceed 80 characters I Specification of flatfields If the identifier FLAT exists the given file will be used by the pipeline If FLAT is not present the appropriate flatfield is automatically selected using the FILTER name I The FILTER names are expected to be 10 characters long followed by If the name is shorter blanks have to fill up the remaining I DOSIULOHS I Maximally 100 lines are read in I VERSION 20 1 720 03 Bad Pixel Mask BPM O2K_UTIL pipeline CAL bpm_part_blown fits I Dark Current Frame DARK O2K_UTIL pipeline CAL dark_current fits Flatiield with priority IIFLAT O2K UTIL pipeline CAL FLATS H flat best f fits I Flatfields for all filters for automatic selection 1234567891 path name J O2K UTIL pipeline CAL FLATS H flat best J fits H O2K UTIL pipeline CAL FLATS H flat best H fits K O2K UTIL pipeline CAL FLATS H flat best K fits K PRIME O2K UTIL pipeline CAL FLATS H flat best Kpr fits NB1237 O2K UTIL pipeline CAL FLATS H flat best fits OMEGA2000 manual doc 14 1 1 Online Mode Online Reduction Scheme ONLINE DATA R
13. Once the linux desktop is available you launch the terminal emulation as follows X 1 vt08 query fire35 This connects directly to the fire35 You may also access other machines via the host chooser if you type instead X 1 vt08 indirect It is possible to toggle between the LINUX desktop and the X terminal with the function keys Alt F8 OMEGA2000 terminal Alt F7 LINUX destop To stop the additional xserver type killall X to kill it give an additional 9 On the LINUX PC besides the usual environment you will soon also have the possibility to work in a WINDOWS environment with Microsoft Office Furthermore a DVD burner is available to backup your data Figure 67 Dual screen X terminal to the right operates the camera The screen at left 1s for telescope operation Appendix 12 Basic MIDAS commands To use the observing utilities measuring seeing etc it 1s helpful to display a flatfielded m age Here are the basic steps for those not familiar with MIDAS replace italics with actual names values Creating a normalized flatfield statistic L tlensmestits displays the information on the frame statistics compute flat filename fits median Use the median from the statistics command to normalize your image Output will be in BDF format Flatfielding an image compute test filename fits flat Display image on the screen load test Soez ceer20 912 0c0b 923500 4500 This will display frame test
14. This will perhaps first adjust the coadd value automatically to smaller values or and than adjust the subitime value to larger values available for Midi as SW coadding with skipping option the of the values are currently restricted to the looping counter inside of ROE2 by maximal value 8191 available for Max128 Max256 as HW coadding w o skipping option continue type USER syntax continue Continues paused macro and commands controls type USER syntax control x xserver f font opens the main camera control GUI window x where to open the window e g xt28 0 SE 2 tont amity 8 9 Luecida counter type USER syntax counter name action set value incr count changes the counter name according to action clears or Gir 7 seus the counter name TER incr increments counter default 1 decr decrements counter default 1 set sets counter to set value examples counter EXPO NO is automatically incremented after each read execution GOUNEET lists the current counters and its values counter EXPO NO shows the counter EXPO NO value counter EXPO NO clear sets the counter EXPO NO to 0 counter EXPO NO in r increments counter EXPO NO counter EXPO NO decr 2 decrements counter EXPO NO by 2 counter EXPO NO set 99 sets the counter EXPO NO to value 99 next read will increment that value saving of current image without read takes the old value to prevent interfering with curr
15. You must enter the full path beginning with You have to set the actual save path to a different directory than the one to be copied Default device is dev rmt 0n for max moritz and dev rmt ln for omega omega and magic omega example backup disk a user dev rmt ln WARNING Use only if you know what you are doing This routine uses dd to copy files from disk to tape Nothing else If you are not sure what this means to your data use tar as backup program e g gt cd disk a max gt tar GVE dev rmt 0 29mnowv96 syntax backup abort Aborts a running backup batching type USER syntax batching n Switches the batching size for GEIRS package streams to number n l Without argument the current status is shown buffers type USER syntax buffer auto manual Switch auto update manual update of buffers If in auto mode after every read all data is automatically added to the appropriate buffer main offset position of UKIRT syntax buffer update This command adds the images of the last read to the main offset telescope position buffers If the data is already up to date the software will send an error message syntax buffer clear Clear maLnjottset buffers All buffer commands are availale with Max UKIRT only cassoff CYPE USER syntax cassoff angle Sets angle as the cassegrain angle for the NSEW orientation zero point CaSSpos type USER syn
16. 398 activity idle st ate tape loaded Figure 49 The GUI of the DA Tspooler Currently only one drive is supported This tool allows automatic saving of data durmg the night on a DDS4 DAT tape A further application of the tool enables to copy data to tape in offline mode A tape of length 150m will hold approximately 1000 images depending of course on the save mode Launching the spool system including the control GUI start datspooler first analyses the status of the tape drives If a tape 1s loaded which already contains da ta a warning is issued and has to be approved by the user Via the GUI the tape can be initialized deleting 1st current content Data format on DAT The FITS files are written as blocked files with a blocking factor of 10 i e record length 28800 Files are separated by an EOF mark Using the spooler from within an instrument programm Usually the instrumentation software calls the via systemcall Call QueueFiles path filename Using the spooler from an xterm Create a list of FITS files to be saved into a file newdata sav e g with ls path fits gt newdata sav path to directory where FITS files are stored Launch the spooler with QueueFiles newdata sav During the tape copy process further files may be entered into the queue Checking the tape content Using the command FitsList one may check the content of a tape The user has to create a file named KEYS LIST with the help
17. Sh NGC 1647 127 Fisure 52 Focus Held at RA 9B IMIG Hansa ara ERA 128 Figure SP OCUS Held at RA S Die ou ak ea aet Gi 129 Figure 54 Focus Held at RA ZE ao rH e de ae aeii 130 Figure 5 Focus Held at RA ce 22 oe ero ipo E Ala MOMS 131 Figure 56 Elevation plots for focus fields January and April 132 Figure 57 Elevation plots for focus fields July and October 133 Figure 58 Astrometry field at RA 2h finding chart for astrometric stars from M2000 135 Figure 59 Astrometry field at RA 5h finding chart for astrometric stars from M2000 136 Figure 60 Astrometry field at RA 9h finding chart for astrometric stars from M2000 137 Figure 61 Astrometry field at RA 13h finding chart for astrometric stars from M2000 138 Figure 62 Astrometry field at RA 13h finding chart for astrometric stars from M2000 139 Figure 63 Astrometry field at RA 18h finding chart for astrometric stars from M2000 140 Figure 64 Astrometry field at RA 22h finding chart for astrometric stars from M2000 141 Figure 65 Elevation plots for the astrometry fields January and April 142 Figure 66 Elevation plots for the astrometry fields July and October 143 Figure 67 Dual screen X terminal to the right operates the c
18. The fields were selected from the M2000 catalogue Rapaport Le Campion et al 2001 These catalogue has a very recent epoch and is complete to V 15 4 Therefore many stars are found in each OMEGA2000 pointing We thank the authors for supplying the data on CDROM The tables with the positional information are available on fire35 as an html file under disk a o2K MANUAL Astrometrie FC html For applications where also proper mo tions have to be taken into account the data from the UCAC2 catalogue have to be used These are also provided under the above path as Astrometrie UCAC2 html SEE FE 2 Mor s si zyj 31 49 300 IB 1a 4 190 12 34 900 t Ta Sedi 14 4 00 We supply finding charts of two types One plots the astrometric reference stars with the brightest stars marked for easy cross reference The second chart 1s a copy from the red DSS II Both have a side length of about 16 arcmin We also provide elevation plots for four times 1n the year for optimal selection of the appro priate fields Astrometry 2h 16 95 16 90 16 85 O Lu Q 16 80 16 75 16 70 2 640 2 635 2 630 2 625 2 620 RA h L E d m 4 m m m i v oW P 3 r t ch ERG A z Li z a E m z m a a n a E r i a LI i ah 2 a a Figure 58 Astrometry field at RA 2h finding chart for astrometric stars from M2000 OMEGA2000 manual doc
19. Without a parameter verbose prints status of the verbose flag version type USER syntax version Prints version string of the Software wheel type USER syntax wheel position name or r erative offsetsteps wheel rdb wheel dialog on off wheel focus Oo fp new Move wheel number to named position or returns information wheel is the logical wheel order from 0 n as shown by the answer of the command wheel itself example wheel returns overview of all wheels reads and shows current wheel positions wheel 2 returns information about wheel2 wheel 2 wollaston45 moves to wollaston45 element wheel 2 rel 25 moves wheel2 25 steps backwards wheel dialog off switches GUI warnings errors wheel is a background process and should have a sync after it when used in a macro wheel rdb is re reading the wheel and wheel macro database files This command is only valid for OmegaCass and Omega2000 wheel focus on off new controls the relative focus adjustment for the selected wheel element combination wheel focus off deactivates the focus correction ot all filter wheels for the next wheel filter commands until it is reactivated wheel focus on re activates for the next wheel command the LOCUS correction Of all filters which are con tagured For CGHKPOCUSSCOPPSScCIOm An the wheelN instrument configuration files wheel focus new updates the relative focus correction informa t
20. frame contains not only the signal collected during exposure but also the reset bias and noise as in the previous mode therefore this readout scheme is also suggested only for engineering function Reset Integration Read 1 line 1024 line 1 line a 1024 line Figure 18 The scheme of non correlated sampling reset read Correlated Double Sampling or Double Correlated Read The scheme of Correlated Double Sampling CDS consists of a complete frame reset a read out of the full array an integration and a readout of the complete integrated frame The reset and the first readout of the frame are not simultaneous i e a slow reset is applied Figure 19 The output signal 1s obtained by the subtraction of the reset frame from the integrated one which eliminates the reset noise and bias from the signal value Since the whole array must be clocked three times one full frame reset and two readouts of the full frame the efficiency of this readout scheme 1s only 33 at the minimum integration time Nevertheless it allows to check linearity of the detector and to create a bad pixel map of it If we apply long integration time without IR illumination of the array then a dark current map can also be created Reset Read Integration Read 1 line 1024 line 1 line a 1024 line 1 line PE 1024 line Figure 19 The scheme of correlated double sampling reset read read row time Figure 20 A
21. nels of the detector namely eight per quadrant Each output provides data from 128 consecu tive columns The Eight Output Shuffled Mode 1s similar to the previous one except the data from each block of 128 columns is cyclically shifted to the next output bus In normal opera tion of OMEGA2000 the Eight Output Unshuffled mode 1s preferred because of its high speed The background limit will be reached in broad band imaging with HAWAII 2 array on OMEGA2000 in a few seconds Series of images are therefore required to achieve sufficient S R so it 1s very important that the array can be read out as with the minimum dead time The minimal integration time is given by the frame readout time and for all readout modes it 1s order of one second All the modes can be characterized with their efficiency that 1s the ratio of integration time to a total cycle time required to obtain an image There are several readout modes feasible for OMEGA2000 but some of them are used only for engineering function OMEGA2000 manual doc Reset Level Read The readout of the reset level of the full array has the simplest readout scheme first the com plete frame is reset then read out A line reset is implemented for HAWAII 2 FPA which means that one reset pulse always resets a complete line of pixels and the chip needs 1024 pulses to reset the full frame while clocking through the horizontal shift register It allows to accomplish the reset readout cycle in two ways
22. posures are stored individually Saturation The saturation level above which the procedure will be aborted 13 2 1 Operating the flatfield lamps The lamps are permanently mounted on the southern telescope base They are either operated via the GUI 1 or via shell commands To launch the GUI type ffl amp in any xterminal on the fire35 The GUI will pop up Quit If you want to operate the lamps from shell commands as is the case with the above com mand o2k domeflats in MIDAS the GUI has to be shut down via the QUIT button first Shell commands flats ALLOFF turn all lamps off flats Li on turn on lamp i i 1 4 flats L5 on lev turnon lamp 5 with level lev lev 0 9 flats Li off turn off lamp i 13 3 Taking twilight flats Function call o2k skyflats ident level coadds number offsets check saturation time Remark o2k skyflats is an OMEGA2000 context command which calls the routine skyflats prg The routine can also be called without the context command in the fol lowing way O2K_UTIL obs_macros skyflats Defaults ident no default level 20000 maximum level in a single exposure to be 15000cts coadds 2 exposures are added up in memory to a single image number 5 take 5 images offsets 0 30 offset telescope between read cycles not exposures by 30 in DEC no offset in RA check check saturation 20000 40000 saturation and monitoring limit time dusk Examples e
23. s immediately batch stream to PKGOUTPORT intf save b s filename immediatelay writes the batch stream to a file save t filename wirtes as a single FITS table file save g s immediately DCR img stream to PKGOUTPORT intf save g s filename immediately DCR img stream to a file Current PKGOUTPORT interfaces middi dif dev PCDxx save is a background process and should have a sync after it when used in a macro set type USER syntax set macropath pathname Print or set path for macros syntax set objectpath pathname Print or set path for object files shminfo EYRE ENG syntax shminfo x xserver n 4d t sec Opens a window to display shared memory info page entries x where to open the window e g xt28 0 n of entries default 6 t seconds of pausing Sky type USER syntax sky filename Writes filename at keyword SKYFRAME into the FITS header slee type ENG syntax sleep Suspend execution of shell macro for seconds This is the same as with sync none sndwin type USER syntax sndwin Opens the sound selector window You may also set the volume and the output channel sound type USER syntax sound on off o speaker headphone v 0 100 Enables disables sound after some operations like read filter aperture lyot telescope macro or as a warning if the saturation check is on Default is off o output headphone
24. 0 12 over a distance of more than 600 1 01 is MIDAS Q25EP Lir H J Roeser MIDAS O2SEP 1 O05 Table Pe refer 1 005 Colums X ir v i DistRatio Scales 5 00654 Y O 000164772 ta rhy NA ntm bane Fly pom gg o te LERNTE NEO divise eae YZ DistRatio Selection AL Date 16 Mar 2003 Time 20 27 13 DistRatio 0 995 0 995 200 300 400 500 R arcsec R arcsec Figure 26 Centre to corner image distortion of the OMEGA2000 optics The ratio of the distance to a star at the centre for all objects from the measured position on the detector using the scale determined from the astrometric solution to the distance calcu lated from the RA and DEC positions 7 3 Filters For OMEGA2000 a set of 24 different filters 1s provided see Appendix 1 for a complete list and filter characteristics Inside the dewar we have three filter wheels with 7 openings each As we need one free opening per wheel and one wheel holds an alu minium blank for dark exposures we can keep 17 filters inside the dewar at one time Two additional positions are needed for two blocking filters as the detector is sensitive to beyond 2 6u the blocking limit specified for the filters Whereas the standard broadband filters J H K and K and the most commonly used narrow band filters like the Hz 2 122u with detector the respective continuum filter will always be available the re maining
25. 3 4 A x and y FWHM histogram of all found objects An FWHM vs intensity plot with the used cutoffs The FWHM histogram of the objects selected The final plot with the x and y focus parabola and values for the best focus and the seeing This plot is automatically saved as ps file with the filename corresponding to the name of the masterframe The first three graphs may be suppressed be setting the graphics output flag to 0 Interalty plut oF 31 object DE ILE LB I Nek TIH uam NRCU TU i E gt i P h Ht m 1 z a E a La xh Zo LE zo Lil LJ Loe JLEHT Linderaltiy we 1 106 Arceec Fozus 24335 3 BELLA CEUTE Aci zc BO HHI aie BED ZR pre mare m Tid eco Poe Ci lon Islerorm OMEGA2000 manual doc 13 5 Tip Tilt Determination The tip tilt determination routine 1s based on an old version of the omega focus routine and needs some preparation steps before it can be properly used Since the detector tip tilt 1s only determined a few times and is not a general user task the routine is not optimized for user friendliness The different steps for obtaining a local focus mask are Preparation e The tilt routine does not take images Focus images have to be taken with the normal o mega focus routine described in Section 13 1 e The fits focus images have to be converted into bdf format with filenames consisting of a 5 character root name and a 3 digit
26. 7 Exposure times for twilight flats OMEGA2000 manual doc Appendix 3 Detector properties Read out modi e o2dcr double correlated read e fcr double correlated read with fast reset e lir ine interlaced mode recommended mode Make sure the idle mode is set to wait Check with idle in the camera window red back ground In this mode the detector 1s linear to better than 1 up to 25 000 cts The observing utilities assume a linearity up to 20000cts to be on the safe side 100 50 50 100 150 200 250 300 deviation from linearity cts 350 400 450 0 5000 10000 15000 20000 25000 30000 35000 40000 45000 level cts The detector should be operated in 32 channel mode default to be selected during start up Please note that the read out electronics has to be reset with power off on after the mode is changed from 32 to 4 channels and vice versa Detector saturation The detector is sensitive towards over exposure and shows an increased dark current fol lowing over exposure Should this accidentally happen e g during taking twilight flats the detector should be read out several times with the blank inserted This 1s best done in endless mode and the count level being monitored on the online display Appendix 4 DAT spooler drive_O ad EI spooler rmt Q Off online INIT EEWIND UNLOAD TAPE LIST files on tape
27. J H and Ks Due to the large field of view there will always be stars from this catalogue in the field for calibration The 2MASS cata logue may be accessed via the web page http www ipac caltech edu 2mass releases allsky 1index html OMEGA2000 manual doc 7 OMEGA2000 filling tubes outer nitrogen vessel dewar readout electronics warm mirror baffle inner nitrogen vessel detector unit filter unit cold plate cold baffle entrance window Figure 14 OMEGA2000 on the frontring cut away CAD draing 7 1 Detector The OMEGA2000 camera contains a focal plane array FPA 777 of type HAWAII 2 by Rockwell with 2048 x 2048 pixels each 18 u wide It is sensitive from about 850 to 2500 nm We provide in Figure 15 a measurement from ESO red together with the actually measured values in the three broad band filter J H K fo our detector blue A histogram of pixel values in a supposedly homogeneously illuminated image is show at right where the median pixel value is at about 250 The corresponding two dimensional sensitivity map is given below We summarize the main detector characteristics in Appendix 3 1 5 105 I 1 0 105 Frequency 50000 1000 1500 2000 2500 30 O 100 200 300 40C Wavelength nm Pixel value slope cts sec Figure 15 Quantum efficiency of a HAWAII 2 detector Finger 2002 as a function of wavelength left Varia tion of quantum efficiecy across the detector fo
28. Menu selects the colour look up table for displaying images gray is a black and white colour look up table e temp is the standard temperature colour table bb is the standard blackbody colour table MagMode Menu switches between the zoom window and a measurement of the image seeing e Magnifier Zoom window this is the default mode e FWHM log Measures the FWHM of the indicated object each time a new image is displayed and plots a running history of the values This is useful for rough focusing Note that to get reasonably accurate measurements of the FWHM the aperture of the box used set with radius see below must be large MagMode v Sul Haqnifier FHHH Log enough to include a couple of rows of sky pixels around the ob 444 2419 ject you are measuring Pixel Radius min max mean dev FWHM flx First Last When the cursor is in the image display window the pixel position and counts in that pixel are displayed here Sets the radius of the small cursor box in the image display See the above note on FWHM log about measuring the seeing Show the minimum and maximum values of the pixels within the cursor box Shows the mean and standard deviation of the pixels within the cursor box Shows the FWHM and total flux in counts of an object selected with the cur sor box Controls the display of a series of images Unless you need to review a set of images to determine for example whethe
29. Observing The white X terminal is ment to host observing commands that take a long time to execute e g the ok2 dither Section 13 6 1 page 64 This way one can take a closer look at previous images or results from the pipieline in the quick look terminal This is MIDAS session 32 9 4 3 Pipeline The yellow X terminal is reserved for executing the online data reduction with the OMEGA2k pipeline Section 14 page 77 This is MIDAS session 33 Any further MIDAS sessions launched with inmidas p 11 where 11 is the session number must not use the session numbers 31 to 33 A few basic MIDAS operations e g to display an image are given in Appendix 12 In general all UNIX commands can be issued from within MIDAS if they are preceeded by sign OMEGA2000 manual doc 9 5 Taking data The windows introduced thus far are the environment in which one takes data manually in cluding the use of GEIRS macros see Section 10 This is useful for tests or special calibra tions For taking standard calibrations darks flats focus the telescope and dither science frames it 1s strongly recommended to go to the MIDAS environment and use the procedures described in Section 12 9 5 1 Setting up the camera for an exposure Before you start make sure you have selected the proper paths for your data etc see Figure 36 at upper right You should also set the root name of the files to be stored on disk which is also done in the
30. fits foc H0010 fits for the focus analysis only The best estimated focus was 24000 microns The integration time is in this instance only used to compute a saturation cutoff for the object selection e o2k focus help OMEGA2000 manual doc Shows help text o2k focus prompt Inquires all parameters interactively Parameter explanation External command line parameters E PZ P3 P4 Po PG P 7 root Root name of all relevant images The full image name is expected to consist of the root and a 4 digit index e g foc _H0001 fits with root foc_H The indices of the input images must be consecutive numbers If no root is specified the current image name in the instrument GUI is used as file name This mode is only possible if new focus test exposures are taken index Index of the first 1mage 1 e the image with the lowest focus setting focus estimated focus step size Best estimated focus in microns and focus offsets between two test exposures in mi crons number Total number of images for the focus analysis The input has to be a odd number lar ger than 3 If an even number is specified it will be converted to the next odd number itime total integration time per image single integra tion time Integration times in seconds The first number specifies the total integration time per image the second one the integration per single exposure which will be co added to yield one integrated image
31. hope to solve the colour problem in the near future with the LINUX PC to be used as an X terminal with the dual screen 9 2 Start up Starting the GUI by pressing the OMEGA2000 button will show the start up screen Camera Omedga2000 o Camera Optic wide field Camera Output 32 channels Data fdev fpcdl s dewv pcd RO Electronic Temp Controller Telescope Focal Ratio f 2 35 Status Figure 34 Welcome screen of GEIRS to start the instrument Please enter your name as observer the rest should be set as in the figure After you give OKAY the GEIRS windows GEIRS Generic InfraRed Software appear and the desktop shown in Figure 35 will appear please note that in this example the telescope had been switched to OFFLINE Therefore the telescope GUI is not shown Omega2000 Display v357 sv9b x04 1 Gmega2000 Controls w357 1 Filev Filer zb 7 Jelleutsi Save Options focus series frame your comment w Pause Abort Pipeline A a a a A es RET m OMEGAZK il D 4 zo 2 i Figure 35 Desktop to operate OMEGA2000 with the camera control the online display and the log window OMEGA2000 manual doc 9 3 The GUI s windows 9 3 1 Camera control window This 1s your interface to the OMEGA2000 camera Fields are changed by clicking into them However editing in the fields 1s not possible You always have to type your text anew In the top r
32. in creases only with the square root of the integration time If the measuring aperture 1s adjusted to the seeing then for stellar images in the background limited case the exposure time increases with the seeing squared if aiming at a constant S N 2 2 wef Z Sxr N F background S N ratio integration time Figure 11 Signal to noise ratio as a function of integration time For narrow band imaging a detailed knowledge of the exact filter transmission and the loca tion and strengths of OH emission lines within the filter range is mandatory 5 Imaging strategies With OMEGA2000 the standard observing goal is to survey a large area on the sky in one or more filters For this type of observations the main challenges are field coverage and back ground subtraction 5 1 Mosaicing a field Covering a large area on the sky with a detector of lim ited field of view FOV poses two problems Image distortion due to imperfect optics and field rotation due to the telescope mounting in our case the parallactic mount of the 3 5m telescope For OMEGA2000 the quality of the optics 1s excellent with a centre to corner distortion of 0 12 only Fur thermore no chromatic effects are measurable Field rotation is unavoidable Assume two objects with same RA are located on the central detector column in one image Then the vector connecting these two objects Figure 12 Field orientation in a mosaic of wil be inclined in the a
33. in current directory std default prints averages and deviations over all pixels in all images of each single channel and the same for the whole image with additional stdv of channels stdv med prints the median of all channels of each single image var prints the median of all pixel averages time direction and the median of all pixel variances time direction f nL n2 use mages nl through na ORLY 1 9 test VAr i LI SC am use quadrant output only e g test var q 1 this options is only available for var option trigger EVPES USER syntax trigger extern wait intern trigger switches between external HW triggering and internal starting OL ROE Vila SW This Option 18 currently only used in MIDI Options are extern starting read waits on data from ROE endless wait synonym to extern intern read starts also the ROE data directly MIDI uses extern as default where for all other instruments without internal trigger there is only an intern trigger Without argument it just prints current status userstatus EVE ENG OMEGA2000 manual doc syntax user Prints user status astronomer engineering superuser verbose type USER syntax verbose on off yes no If you set verbose yes you will get more output to the screen e g while executing a macro the system will print every command and the line number so you always know which macro line is executed Default is yes
34. made of fused silica with a diameter of 350 mm and a thickness of 20 7 mm The liquid nitrogen is stored in two vessels that can be filled on the telescope through the up per side of the dewar One of the nitrogen tanks is directly connected to the inner radiation shield and is referred to as the inner vessel in the following Its capacity is about 47 litres The movable bate in lower positi Gn OMEGA2000 manual doc outer vessel with a capacity of about 72 litres is connected to the second shield Both nitro gen vessels are only filled half to allow a maximum tilt angle of the telescope of 90 e g for balancing of the telescope and nitrogen filling in the prime service position see image on cover With both vessels filled up to half of their capacity and all cooled parts in thermal equilibrium the dewar retains a temperature of 77 K for about 34 hours 7 6 Read out electronics IR array Rockwell HgCdTe 2048x2048 HAWAII 2 outputs END EJ __ power clock Datalink parallel serial Datalink parallel serial parallel I O PCD 60 parallel I O PCD 60 m serial I O HU om network Figure 30 Block diagram of the read out electronics 7 7 Control electronics As the read out electronics the control electronics is also mounted in racks on the front ring Both are sealed in cooling boxes to carry away the heat produced during the observations The control electronics
35. me dian like procedure and this 1s then subtracted from this particular science frame see Section 14 for details This procedure has to be taken into account planning observations For extended sources dithering this way 1s not appropriate as no pixel will see pure sky in most of the images Therefore additional observing time has to be included to measure the sky level by offsetting the telescope by amounts large enough to bring the target out of the FOV Variations in the shape of the night sky emission cannot be removed this way however In order not to loose too much telescope time with sky observations whose S N per pixel should be larger than the object frame in order to preserve the S N of the science frame during sky subtraction one should smooth the extracted sky frame see Sections 6 17 and 6 18 for de tails In the MAGIC manual this is called the moving sky technique 6 Image calibration 6 1 Focussing the telescope onto the detector The optimum telescope focus changes mainly with temperature of the telescope structure For the 3 5m telescope this change is 165 u C A smaller effect is introduced by flexure of the telescope mount Once an initial optimum focus is found the automatic focus compensation by the telescope computer takes care of most of these changes during the night So the main task 1s finding an initial good focus This is accomplished by a focus test series during which the telescope focus position
36. moving to an absolute position or offsetting from the current position 1s done on the telescope control panel The basic information from the tele scope such as airmass UT and current telescope position is also displayed here This GUI panel should start automatically when the GUI is first initialized If not you can call it up from the camera control window in the menu Modules File Menu e SAO map Calls up a separate GUI panel which shows the area of sky where the tele scope 1s pointing including nearby SAO stars This panel 1s described in more detail below e Airmass Graphical display of the current airmass and plot of the airmass history for the currently set object e Quit Quits the telescope control panel but not the GUI This module can be restarted from the modules menu on the camera control panel Moving to an absolute position An absolute position can be entered directly in the RA and Dec windows After setting the equinox the position can be sent to the telescope by clicking on the move button Note that the telescope does not actually move only the coordinates are sent To move the telescope you must press the go button on the old telescope controls The RA and Dec windows also display the current telescope position after each offset Relative offsets Offsets in arcseconds can be supplied in the dx and dy windows Clicking on one of the directional buttons in the compass panel will then offset the telescope by the r
37. o2k skyflats dusk H Take 5 exposures with 20000cts pixel Offset the telescope between images i e after 5 exposures by 30 in declination only e o2k skyflats dusk H offsets 60 60 Same as above but with offsets RA 60 and DEC 60 e o2k skyflats help Shows help text Parameter explanation External command line parameters Pl ident Identifier for the images to be taken P2 level Desired count level for a single exposure in counts pixel P3 coadds Number of exposures to be taken in a read cycle OMEGA2000 manual doc PA number Number of read cycles to be taken This 1s also the number of different positions on the sky used for the flatfields P5 offsets RA offset DEC offset Telescope offsets to be executed between read cycles not exposures P6 check Determines whether the exposure level 1s checked in a test exposure after each read cycle Use no check to suppress checking Py Setuuration SODIUCOEIHOg limtt Saturation level of single exposure and maximum level until which the level monitor ing should be executed P8 time of day dusk or dawn Specifies whether evening or morning flats are taken This determines the behaviour of the level monitoring Functionality The filter and read out mode have to be selected manually before calling this routine The procedure takes test exposures with the minimum available integration time to calculate the time needed to reach the desi
38. of the detector in which the volt age on the pixels can be measured without affecting charge collection During the detector reset a constant voltage is applied to all pixels Incoming photons delib erating charge in the detector substrate reduce this voltage Saturation occurs if the voltage has been completely reduced by the photons This process of signal detection storage 1s the major difference to a CCD where charge is collected in a pixel leading to smear out effects in case of saturation The following figure from the PhD thesis of Martin G Beckett 1995 gives a vivid discrimination between a CCD and an IR FPA Empty saturated Figure 5 Difference of detector saturation between a CCD and an infrared detector OMEGA2000 manual doc 3 2 Read out techniques in general The figures below are a schematic representation of the voltage on an individual pixel as a function of time At the beginning of an exposure the voltage is set to a predetermined value by a reset When the reset switch is opened the voltage will jump to a variable new level the pedestal and then increases linearly with time as charge from photoelectrons and dark current accumulates in the detector This process continues until the detector is reset to the original level at the end of the integration The linear behaviour of most modern detectors spans the range from zero charge to over 90 of the total capacity A v reset l reset voltage KT
39. out mode is similar to the double correlated read but here the readout cycle contains 2 X n readouts instead of two After the complete frame reset the full array is read out n times and the average of the n frames provide the bias values of the pixels after reset After the inte gration the complete array is read out n times again and the average of these frames is taken as the integrated signal Figure 25 The video signal is the difference of the two averaged frames Although this readout mode allows a stable operation the duration of one readout cy cle is in order of seconds even if a fast reset is implemented which may cause the minimal integration time to be too long Reset 1 Read s n Read Integration 1 Read bes n Read 1 line 1024 line 1 line ME 1024 line 1 line b 1024 line 1 line NE 1024 line 1 line 1024 line Figure 25 The scheme of the multiple end point read The single pixel read The read out cycle starts a full frame reset line by line then only one pixel is read out per channel or quadrant according to the Four or Eight Output Mode Thus the data of a full channel or a quadrant consists of the value of only one arbitrarily chosen pixel This mode is only for engineering purpose OMEGA2000 manual doc 7 2 Optics The optics consisting of 4 lenses made of CaF fused silica FS BaF gt and ZnSe is achro matic between 850 and 2500nm The centre to corner image distortion is almost negligible
40. positions will be equipped with filters requested for the up coming semester As we plan to open the dewar at most every half year it is mandatory that you clearly specify your filter needs in the application for observing time It will not be possible to use special filters on short notice detector primary mirror 7 4 Baffles floor Due to their sensitivity to the surrounding thermal emission from d d tel acad d laborate bt Figure 27 Working principle ome and telescope infrared cameras need an elaborate baffling ofthe movable warm baffle system For systems with an intermediate focus like OMEGA with only a cold baffle top Cass a cold Lyot stop is the most efficient way to block back rays from outside the pri ground light This is however not possible in the optical design mary reach the detector of OMEGA2000 We thus have to rely on a set of warm and cold These may be blocked by the movable baffle baffles that are meant to reduce the background signal e A cold baffle at the dewar entrance win dow is placed as far from the detector as feasible to narrow down the solid angle of warm background seen by the detector In order not to vignette the signal from the sky this baffle still allows the detector to see parts of the warm dome floor e A fixed warm baffle with the shape of an ellipsoid whose foci are at the rim of the cold baffle reflects rays from inside the dewar back inside Rays from
41. prohibit scattering light into the light path A big advantage of domeflats is that one can use the amble time in the af ternoon to take the flats Thus S N is normally not an issue To eliminate the thermal emission of the screen and dome surroundings one has to take flatfields 1n pairs with lamp on and lamp off The actual flatfield 1s then the difference image lamp on lamp off This at the same time eliminates any dark count signal from the detector A procedure to take well illuminated dome flats 1s described in Section 13 2 6 3 Dark current Even if covered by a cold aluminium blank in the filter wheel pixels may show a time de pendent signal the dark current Most pixel are well behaved in that their dark current is neg ligible or scales with exposure time Fore these the dark current can be modelled and sub tracted We provide two files which give constant and slope of a linear fit to the dark signal as a function of time to correct for this see Section 13 10 on page 74 for a MIDAS utility to create these files from a series of dark exposures Again care has to be taken not to destroy the S N of the science frames by a bad dark frame with insufficient S N All pixels not following a linear relation between exposure time and dark signal are treated as bad pixels and are represented in the bad pixel mask 6 4 Bad pixel mask Dead pixels or pixels with an uncorrectable dark current hot pixels have to be interpolated from the
42. remain fixed for the future However the orientation of the detector s Y axis may change slightly when the in strument was dismounted or especially if for any reasons the detector had to be removed To easily check the astrometric properties we supply a list of astrometric fields with a sufficient number of astrometric reference stars from the M2000 catalogue Rapaport Le Campion et al 2001 These are listed in Appendix 8 where finding charts marking the stars from the M2000 catalogue as well as copies from the DSS are provided Elevation charts facilitate selection of a suitable field throughout the year Tables of these stars as well as a subset with proper mo tions from the UCAC2 catalogue are provided on fire35 as html files in the MANUAL path Pixel scale is 0 44942 0 00005 pixel in the NB1710 filter 6 7 Photometric calibration For a rough photometric calibration we provide the expected counts in all the filters for a 0 magnitude star in Appendix 9 For a more accurate calibration photometric standard stars of known broad band magnitude are needed and we reproduce the standard lists from the litera ture and other observatories in Appendix 10 For narrow band imaging the calibration via these stars may be problematic depending on the accurate spectral run within the bandpass For these synthetic photometry may be more appropriate and we hope to supply the relevant data 1n the near future The 2MASS catalogue provides magnitudes in
43. saved by pressing ve OPTIONS the SAVE button at the beginning of this line or by issuing filename z0146 a save command from a script One can either specify a from e eL name or a root In the latter case the filename is the root arean 1 1 2048 2048 plus a four digit integer which will be automatically in crement by one each time a save is executed By specifying integrated el the root the system looks for the highest free filename If a F1ITS cube ET filename ends with a number this number will be increased FITS table FT batches Save Options Calls up a save configuration panel which SUME defines the default way in which to save images The main taw dump E choices are whether to save individual exposures as sepa aute save ET rate disk files or to integrate them sum and save only a immed save ol single disk file Note that the save options are overridden by any options specified in observing macros For example save f 2 1 in a macro will integrate from image 2 to the end of the series and save only a single file even if the Figure 38 Save options window save options specify saving images separately Turning on auto save will execute a save after every read without clicking on the save button Test gives test as a root name for the next image which will not be saved to tape After the test exposure the previous file root name is restored Object is the object name which i
44. secs FRAMENUM 1 OF 1 SKYFRAME junk0012 SAVEAREA 1 2048 1 2048 TEMP A 0 000000 sensor A K TEMP B 0 000000 sensor B K Weitere Temperaturen mit genauer Angabe wo gemessen im Kommen Meteorologie Daten Seeing Monitor SOFTWARE Version 340 Mar 27 2003 18 28 17 e bergang zu hierarchischen Keyword Namen e World Koordinaten einf hren e Reihenfolge und Gruppierung der Keywords OMEGA2000 manual doc Weitere Keywords in Anlehnung an MOSCA DATAMAX 65535 0 Maximal pixel value DATAMIN 0 0 Minimal pixel value DATAMEAN 8085 4 Mean pixel value CTYPE1 PIXEL I Pixel coordinate system CTYPE2 PIXEL Pixel coordinate system CRVAL1 240 7 Start Point rel Lo 1 Phys pixel in axis il CRVAL2 501 0 Start point rel to L phys pixel ih axis 2 CRPIX1 1 07 inerement of axis L an plxels binning factor CREPIXA2 1 0 g increment ot axis 2 in Pixels binning Factor CDELT1 1 0 Binning factor along X CDELT2 qud Binning Tactor along Y PCO01001 1 00000000 Translation matrix element PCO01002 0 00000000 Translation matrix element PC002001 1 00000000 Translation matrix element PC002002 0 00000000 Translation matrix element EQUINOX 0 000000 Equinox in years RADECSYS NN ES IMAGETYP science Type of observation HIERARCH CAHA TEL GEOELEV 0 elev above sea HIERARCH CAHA TEL GEOLAT 37 2236 geographic lat HIERARCH CAHA TEL GEOLON
45. shorter sequence OMEGA2000 manual doc 4 Sources of noise signal to noise ratio and exposure times When planning observations the basic task is to estimate the integration time necessary to achieve the required signal to noise ratio S N The following sources contribute to the noise Sky background S counts pixel sec Dark current D counts pixel sec Read out noise R electrons pixel read Object flux F counts sec The S N achieved for an object of flux F counts sec spread out over a circle of radius r on the detector pixel after an integration time of At seconds is then S F xAtx EPC N F S D xzr xEPCxAt zr x R Here EPC is the conversion factor electrons per count The integration time should as a minimum be so long that the denominator in the above for mula is no longer dominated by the read out noise Ignoring object flux and dark this requires 2 AR au S x EPC Due to the variability of the night sky this integration time should also roughly determine an upper limit to the integration time Optimisation between adequately sampling the brightness variations in the sky background avoiding to be detector limited and keeping the number of data files at a manageable level is the primary objective in planning infrared observations The S N at short integration times i e in the detector limited range where the noise is domi nated by the read out noise is proportional to Ar In the background limited regime S N
46. sky tot single of the total object observation time Note To prevent truncation errors when calculating the number of repetitions tot pointing should be a multiple of tot single and tot single should be a multiple of single The single exposure time single 1s also used for the sky observations thus tot single sky should also be a multiple of single move Distance of sky field from object in arcminutes direction Direction from object for the designated sky field Can be set to N S W E for a des ignated sky field North South West or East of the object If set to ALL 8 different sky positions located around the object at the specified distance are used object identifier PE P Po Character string for the IDENT descriptor If blanks are contained the string should be enclosed in Start pos Start position of the dither seguence This parameter allows the continuation of the dither pattern at a specified position after an interruption The telescope 1s expected to be in the start pos 1 th position from where the dither pattern 1s continued with the next position pointing Identification integer for the descriptor POINT NO Can be used for easier data iden tification SEASSDE Flag for dither offset mode offsets 0 gt the offsets will integer multiples of the pixel scale offsets 1 gt non integer offsets are used for the dither offsets offset name gt gt the offsets are specified in a file wi
47. syntax system emd Executes any system command where cmd might be any combination of arguments On problems with special characters surround the cmd with the character Example System abae uq NOS to send escape to tv guider System tvgcmd to get information about tvgcmd Waits for termination of the system call to Evpe ENG syntax tO 4 oet timer Q to 4 milliseconds ERE electronies only ti LVDEJ ENG syntax tl Set umero co 4 mulbLrsecondse TREESLEGE ror ms only t2 EPE ENG syntax t2 4 Set timer 0 to milliseconds IRL electronics with Max Omega only tdebug type USER syntax tdebug text anytext anytext Writes an entry Into the debug Sju er Mod file cum the Lorm 2004 05 28 11 23 41 3794 ZD ocass logentry all what you typed OMEGA2000 manual doc telescope ype Syntax USER tele scope abs solute hr min sec dg min sec equinox Moves the telescope to the absolute position alpha hr min sec delta dg min sec cele abs must not be used within a macro syntax tele scope rel ative zero or dalpha ddelta Moves the telescope dalpha ddelta arc seconds tele rel zero sets the relative offset sum to zero tele rel shows the relative offset sum tele is a background process and should have a sync after it when used in a macro syntax tele focus 4 Move telescope focus units micron syntax tele pos ition Reads the tel
48. un A RO RE 43 P OUCRIOOE esse a os Migrate ie edad ADO 43 04 2 ODSeLVITID eat 43 93 9 PADS MING uu u saka sana makansaqtass qayaqa doin datnivnmu itus deserat eto donus te sedens 43 AS TIKT Qatar 44 9 5 L Setting up the camera for an eXpOSUEe ae 44 9 5 2 Takina EPOSU es enlarge 44 9 5 3 Image inspection with the real time display 44 DSO sO AVA UE zesinn aT o ta LAO A zwi dnt coeno a A SG oS OD oce Cem apas 44 O Te OD ECT CALAIO CUES tete abus Font ue E a Foto abae 45 OSMIO ETENIM 46 11 TOUTES WOO no Seen meii ee Rt uten coetu balia eu eir OC 48 J ODSCHANE ut ALC Ie eT c 49 12 1 Minimize OV CL NGA ss db eek 49 13 2Observ Ing Bllili uy ge een eins 50 ISl C APTA oi S aa A W A td ange ERY 51 12 DOM ALS eei OO RO AO RARE 53 152 1 Oberaim the Hatfield Tamps asi eie O u bO 54 Jo Takine iwan I see ei a unite qud n Mn Ure 55 E M RSS MIS unn NL 57 13 3 Tip Tilt Deteininalloh ACO A R A tien Cac un tina deco une a dd ades O tU M LE 62 1356 Takins dithered Science Tineinae awu akku 64 WSO Po SUEVEY OVSE Va ONS aan 64 13 62 Extended objects ee ni anu us nsa au 69 19575 MI as ENG Seen unu are res ea 73 13 8 Pixel accurate alionment or the telescope ann ae hu neue 73 13 2 Retative calibration Of survey Telus ae u a a ah ettet 74 13 10 Determining bad pixel mask and dark frame 74 13 11 Monitoring atmospheric transmissi
49. 00 independent dither positions Basic pattern 1s shown in pink Comments The observing macro prepares the online pipeline data reduction The name and path of the image catalogue and the integration time are stored in auxiliary files which can be ac cessed by the pipeline The image catalogue is updated with the name and path of the lat est 1mage after every integration With each new telescope movement the time the offset and the dither number are written into a log file tel pos datej log in the current directory The date in the file name is the date and time the MIDAS procedure was started 13 6 2 Extended objects Function Call o2k sky point icatalog itime tot pointing tot single single tot single sky move direction object start pos pointing offsets Remark The actual routine called is sky_pointing prg and this may also be called by O2K UTIL obs macros sky pointing Defaults icatalog no default itime no default move 30 sky position is at a distance of 30 arcmin from object direction all use 8 different sky positions around object object 1dentitfier no default start pos start at first dither position pointing pointing identification number for header offsets 0 use pixel integer offsets for the dither pattern Examples o2k sky point M51 3600 30 5 20 N M51 in J 2 Take 5 second exposures and add them up in memory to 30 second integrated 1m ages The total integration time for the obj
50. 1 z T E T LL i 3 a A u rza r T im Figure 52 Focus field at RA 9h M67 This field contains also 3 photometric standard stars red circles from top to bottom __ J2000 8 J2000 There are also more than 300 astrometric stars in this field from the M2000 catalogue Focus at 12h a J2000 12 25 25 15 8 J2000 26 59 3 P E gt Pu I L i i E i E r a E a 1 m i Ld M E k E E Bi Jom E m r a amp U F p E a m i F a 5 i I LJ i L z P 1 U h I ss i ET p ma u F I Figure 53 Focus field at RA 12h OMEGA2000 manual doc Focus at 17h a J2000 17 3 37 003 8 J2000 26 59 50 E Jh a 4 a P m x u 4 f m Y E bZ Ka u a K u a i E ug a 2 i ci Fee i a U F F G u z E m i m k 4 E t 11 E p r u r zum m Ta m z U S 3 1 LI i rit 8 EA j 7 F p E r 1 m Y z u E m a z SE F 1 i a E m k E i my F F u E F a a u a a m TE I u E 1 Piko uw m M a T a a z i n E x n lt a m E ik K FE i u 1 a r U 1 a gt i W m m zd Em U I U u lt uh SE P gt
51. 1s systematically varied and the width of stellar images 1s meas ured for each of the focus settings Whereas with CCDs the whole series can be stored on a single frame with the charge shifted between the individual focus settings with infra red de tectors individual frames have to be taken for each focus setting due to the high background which requires short integrations We provide suitable focus fields Appendix 7 and supply a procedure to take a focus series analyse the width of the stellar images as a function of focus value and set the best telescope focus see Section 13 1 6 2 Flat fielding Each pixel of a FPA has a slightly different quantum efficiency than its neighbours Further more there are larger scale variations of the quantum efficiency across the detector To com plicate matters further the quantum efficiency is a function of the wavelength of the incident radiation Thus flatfields need to be taken for all filters 1n use during the observing campaign Vignetting due to the optics and dusk on optical elements produce effects which are similar to the variations in quantum efficiency Illuminating the detector homogenously will not pro duce a constant signal on the FPA Flat fielding 1s the process to correct for all these effects and produce flat images if the illumination would be homogenous Turning the argument around a flat field image 1s a homogenously illuminated frame which can be used to correct the measured sign
52. 2 mode 0 1 sum 7 0 0 Uses the fast true minimum method for the sky determination with a total of 5 frames The intermediate summation result 1s written to disk every 7 object frame High quality reduction for normal observations o2k pipeline icat user specified frames 3 or 4 mode 2 3 sum 7 0 2 Uses the outlier clipping method for the sky determination with a to tal of 7 or 9 frames Only the final summation frames are written to disk Improved quality reduction for observations of extended objects o2k pipeline icat user specified frames 3 mode 0 3 sum 7 0 2 Uses the minimum method with averaging of the 3 smallest values for the sky determination with a total of 7 frames Only the final summation frames are written to disk 14 2 Flowcharts for pipeline eae a mms OMEGA pipeline prg parameter handling 14 2 1 Overview Main Modul open calibration frames IMAGE LOOP p single s Image Reduction open output frames Flat amp Dark Correct DENM Bad Pixel Correction oun O Subtrame Statistics Sky Modelling Sky Subtraction Summation Prep Alignment amp Summation OMEGA2000 manual doc 14 2 2 Sky Determination Image Stack Sky Modelling For Each Individual Pixel Extitaci EN NH Hert Azel Median Jutlier Zlipping Mice Winda Modez MERERI subtract sk y Je Add Cenztantand Unde Hotmah tien IH sky Subtracted U
53. 2 sdB 4 gt s No Q 14 DA3 0 88 0 17 DA2 0 08 0 22 DAI 0 38 0 15 09 B2p Sooo D W O 2 N 0 23 DA2 0 12 DA4 O DN R M U gt 0 15 Var Finding Charts All of the following images are printed with standard astronomical orientation north is up and east to the left The images are roughly 4 arcminutes square a scale bar of 1 arcminute length provides a reference in each image The UKIRT faint standard star in each image is indicated with tick marks I have thus far been unable to positively identify the fields of FS10 FS11 and F S14 so I would not recommend their use at this time In addition a quick search through SIMBAD revealed that FS24 84106 1024 was listed as a variable star In the several observations I have of this standard the magnitude appeared to be relatively constant and at the magni tude given in Casali 1992 but one should probably avoid using this star for accurate flux calibrations of infrared data The finding charts are arranged in numerical order by their faint standard number This arrangement should make it easier to find the images quickly This version is missing finding charts for F518 and FS26 I have the data for these fields I just have to reduce it For users of at Calar Alto the standards FS08 FS09 FS26 and possibly FS25 de pending on the seeing are too bright to be used as standards they saturate in the
54. 6 observations survey 65 OH emission 10 OH emission spectrum 10 OMEGA2000 baffles 27 dewar 28 optics 27 photoelectrons 11 photometry calibration 20 pipeline 78 calibration file 82 examples 89 flow charts 86 pixel size 21 quantum efficiency 21 Rayleigh 10 readout non destructive 11 read out electronics 29 read out mode double correlated read 13 implemented 22 line interlaced 25 mulitple end point sampling 13 sampling up the ramp 13 Read out mode 12 read put mode double buffermg 48 real time display 39 saving data 45 seeing 7 4 signal to noise ratio 15 OMEGA2000 manual doc sky observation 73 tape copy 96 telescope 31 control 41 coordinate zero point 31 tip tilt 31 63 UKIRT Faint Standard Stars K BAND FINDING CHARTS m FS 17 a i ia FS 16 E au BJ e m 1 Prepared by David Thompson Max Planck Institut f r Astronomie Heidelberg Germany Introduction The pointing on modern telescopes is typically good enough to place standard stars some where near the middle of the imaging arrays so one can point and shoot and be reasonably assured that the standard will be observed I still prefer to verify fields as I take data which was the primary motivation in producing these finding charts The construction of the Q prime focus infrared camera for the Calar Alto 3 5m telescope added some additional incen tive as other existing flux
55. CALE 0 450000 arcsec pixel ELECGAIN 4 150000 electrons DN ENOISE 32 000000 electrons read ELECTRON MPIA IR ROelectronics Vers 2 BAFFLE IN OUT W1POS NO W2POS NBl23 7 W3POS OPEN En Y Y Y Y FILIER NB12 3 7 sollte String aus WPOS1 WPOS2 WPOS3 ohne OPEN sein STRT INT 83825 7 23 17 05 start integration UT STOP INT 03832 233117312 stop integration UT RA 3 698861 R A St4175540 DEC 31 222361 7 Dee 37 13 20 5 EQUINOX 20003 284423 equinox JD2000 al ee eel AIRMASS 9 999000 airmass Null setzen wenn nicht verfugbar HAR ANGLE 8 736111 hour angle hours LST 44765 900000 siderial time 12 26 05 EOread T FOCUS 30 000000 telescope focus mm BSP SV J Ss BL Li pe OBJECT normal POINT NO 0 pointing counter DITH NO 0 dither step EXPO NO 186 exposure read counter FILENAME b0012 fits TPLNAME macro template name TIMERO 54 milliseconds TIMER1 54 milliseconds TIMER2 0 microseconds PTIME 2 4 plixeletime units READMODE double corr read read cycle type IDLEMODE break idle to read transition SAVEMODE double corr read save cycle type CPAR1 1 cycle type parameter ITIME 5 000000 on chip integration time secs HCOADDS 1 of hardware coadds PCOADDS 1 of coadded plateaus periods SCOADDS 1 of software coadds NCOADDS 1 effective coadds total EXPTIME 5 000000 total integ time
56. EDUCTION SCHEME ID npe PEL e m E a CC ET a RAR E o QE 7 B Pul s Hu s s RR s LL Lis LL Li Pipeline Online Mode Once an observing macro has been started and has taken at least one image the pipeline can be started in online mode for the real time data reduction There are two ways to run the pipeline in online mode 1 Use the predefined command o2k online without any parameters This command uses the in catalogue information provided by the observing macro and the default calibration file It is using the fast median method with a total of 5 frames for the sky determination The intermediate summation results are written to disk every ga image Note For this command the internal PRG parameters see above have to be set up properly 2 Use the normal pipeline command with online specifications The pipeline is started in online mode by setting the image catalogue parameter to automatic o2k pipeline icat automatic other parameters Th s command also uses the n catalogue information provided by the observing macro but all other parameters can be specified by the user Working with online reduced data Each new output data frame 1s created by the pipeline in the following way 1 Create a plain image without any data 2 Write output data into the new frame 3 Close output image This mplies that the output frames are visible in the reduced data directo
57. EGA2000 manual doc 13 Observing utilities General Remarks The utilities described in this chapter are meant to increase the efficiency in the use of tele scope time OMEGA2000 has the same functionality in terms of user interface and macros as the other IR cameras on Calar Alto Thus users may use their own observing macros All functions described in this chapter are MIDAS procedures and have to be called from an active MIDAS session The context omega2k ctx has to be set for the definition of the utility short cut commands o2k command All routines use the environment variable O2K UTIL which points to the directory o2k utilities All paths are defined relative from this top level directory All routines can be paused during the data acquisition process by pushing the PAUSE button in the instrument GUI The data acquisition is continued by pushing the CONTINUE button All routines can be aborted during the data acquisition process be pushing the ABORT button in the instrument GUI The routines check after every image whether the data acquisition has been aborted i e it can take up to a full integration time before the macro 1s actually aborted During data acquisition the macros should only be terminated using the ABORT button Ctrl C would possibly cause instrumentation problems Outside a MIDAS procedure Ctrl C can be used to abort the current MIDAS command This might however close your MIDAS ses sion and also close the X termin
58. L 1 WHEEL 2 UT universal time FILENAME first filename of this entry number of files in this entry OBJECT object name RA right ascension IT DACS TECE connected else 0 0 DECS declination if DACS TECS connected else 0 0 EQ equinox AM ditmasa lf DACSJ TBCS connected else 1 0 ITIME on chip integration time COADDS number of coadded integrations per file WHEEL position name of wheel ls type Syntax ls EVDO syntax lyot EPDE Syntax macro type syntax EB median type syntax OMEGA2000 manual doc USER ls switches filename Executes ls UNIX style USER ls Print contents of current save directory see dir USER lyot name Move the lyot stop wheel to position name The named positions are defined in the file HOME info wheel2 Without parameter this command prints all possible lyot position names and the actual one lyot is a background process and should have a sync after it when used in a macro USER macro c lear filename Executes the macro filename c clear option is given alone the last macroname is just cleared This macro file contains commands like you use with the shell Be careful when invoking commands like read telescope or filter that run in the background Make sure that the next command does not conflict with the previous or use the sync command The defaultbt drrectory for the macros GS SHOME I
59. OMEGA2000 User s Manual Hermann Josef R ser With contributions from Peter Bizenberger GEIRS GUI Zoltan Kov cs detector Ren Fafbender observing macros pipeline Version 2 4 March 2005 Parts of this manual are based on the MAGIC and OMEGA prime user s guides The OMEGA2000 team P I project scientist Hermann Josef R ser Project manager optics Peter Bizenberger Mechanical design Ralph Rainer Rohloff Harald Baumeister Electronics Bernhard Grimm Matthias Alter Ulrich Mall Mechanics Armin B hm et al Cryogenics Werner Laun Software Karl Zimmermann Florian Briegel Clemens Storz Students Ren Fafbender Zolt n Kov cs OMEGA2000 manual doc Table of contents 1 JH odU UO oet o tetto AA O Ea 7 2 Astronomical observations in the infra red region 8 ZN PM OT nG pi u ei ER 8 2 2 THE MMA Be SS a O om ent ty Salen da tc ebrei hut petiere OWENA 8 gt Dete ina PROTO een 11 3 1 Focal plane arrays for the Iftfra red r 11 3 2 REAd OUL LECHINIGUGS In generale ass 12 SUM Reese Teak UTR 12 3 2 2 Reset read read double correlated read 12 3 23 Multiple end pol t r SSmpline u uy A A sa AR A A EPA de ded 13 ZA Sample u te ra Pere aE AO ein ec 13 4 Sources of noise signal to noise ratio and exposure tlmes
60. S is set to median min sigma me diantmax sigma LABEL cuts P7 flags sky save calibration position screen_output Integer flags sky save determines whether the modeled sky 1s saved or not 0 sky is not saved 1 the sky for each input frame is saved with name sky imagenam fits calibration position position where flatfielding and calibration takes place 0 no calibration is done 1 all calibrations bad pixel correction dark current subtraction and flatfield correction are done at the beginning of the reduction process 2 do flatfielding at the end of the single image reduction bad pixel correc tion and dark current subtraction are still done at beginning screen_output specification of the amount of screen output screen output is suppressed the feedback is only saved in the log file 1 the pipeline feedback 1s displayed on the screen LABEL flags Po calibration frames Specification of the calibration frames The calibration frames flatfield bad pixel mask dark current frame can be specified in 3 different ways l no specification default the standard calibration ASCII file 1s used to ex tract the calibration frames 2 amp path filename an ASCII calibration file is specified A filename ts indicated by a preceding amp e g flatfield amp disk a o2k cal_file cal For the calibra tion file format see below 3 flatfield bad pixel mask dark current frame the calibration frames ar
61. a 4 a r T a HU fe Figure 60 Astrometry field at RA 9h finding chart for astrometric stars from M2000 OMEGA2000 manual doc Astrometry 13h A 17 85 17 80 17 75 DEC 17 70 17 65 17 60 13 287 13 282 13 277 13 272 13 267 RA h Figure 61 Astrometry field at RA 13h finding chart for astrometric stars from M2000 Astrometry 13h B 12 70 12 65 12 60 O LLI Q 12 55 12 50 12 45 13 080 13 075 13 070 13 065 13 060 RA h 4 A r x dr A M E 1 mr M a i N m E I a A i x a I wi n 5 oa z 7 e u m z F a E E i ip Figure 62 Astrometry field at RA 13h finding chart for astrometric stars from M2000 OMEGA2000 manual doc Astrometry 18h 14 78 14 73 14 68 DEC 14 63 14 58 14 53 17 707 17 702 17 697 17 692 gla om et d pum IM d ub L 3 rod 14 m r u Bu Ze Eo horn RA nri d m gt a f au a Pb y ur puer aUe qon i e Ein F U za 3 a si rf FF U A Ls 7 ie aj J a m i I j 3 a a d LN r u gt z U 5 Fre Rn B x E x r F Ine g E E m a 1 f u n ue T 4 Lm u 2 m de a ae kaj m P e a gos A E ur P a u i 7 SG c CUM R D E z P a l S
62. a dea MR s onem D Et C asas 148 Appendix I4 Acronyms used ee u DIM sit 149 5 Reference teaser 150 OS Sub C Hii ee een es oe 151 OMEGA2000 manual doc Appended UKIRT faint standard stars Dave Thompson List of Figures Figure 1 Atmospheric transmission as a function of wavelength in the infrared wavelength range Cox 2000 8 Figure 2 Contributors to the atmospheric absorption in the wavelength range 1 to 6u O Cox 2000 9 Figure 3 Backeround misston sources see Cox 2000 een u le een area aes 9 Figure 4 Schematic structure of a HgCdTe HAWAIR detector 11 Figure 5 Difference of detector saturation between a CCD and an infrared detector 11 Figure 6 Detector readout voltage as a function of tIme 12 Figure 7 ReadzGiit mode resetread a He la DE UU pe das Ee ult edat 12 Figure 8 Read out mode Double correlated read 12 Figure 9 Read out mode multiple end point samplinzg 13 Figure 10 Readout mode sample up the ramp aou uay unu aaa aaa aa aaa aaa at Qusa 13 Figure 11 Signal to noise ratio as a function of integration tlme l4 Figure 12 Field orientation in a mosaic of images taken with a parallactic
63. al In this case just launch the session again If MIDAS com plains about an already open session proceed with yes Documentation of all MIDAS commands is given in the help GUI in the quicklook desktop Furthermore the ESO web pages provide an introduction to MIDAS Please refer to http www eso org projects esomidas doc user 98NO V vola 1ndex html Sounds Some utilities run for a relatively long time In order to alarm the observer if an action has to be taken or if something went wrong sounds are played Please make sure that the speakers are connected properly to o2k1inux The following events are signalled by sounds e Endofa procedure gong e User is prompted doorbell e Result is displayed no immediate action necessary whistle e Abort or error crash e Input error sorrydave If you want to test the sounds please use the shell command auplay disk a staff GEIRS SOUNDS sound name au where sound name is to be substituted by the above given names Please note that the sounds described above are independent of the sounds issued by GEIRS see upper right in Figure 36 for the window where to control GEIRS sounds Most of these utilities have been prepared by Ren FaBbender in the context of his diploma thesis 13 1 Calibration series Function call o2k calser ident time coadds number spacing save reset Remark o2k calser is an OMEGA2000 context command which calls the routine calibration seri
64. al by dividing the images by such a normalized flat field frame As every science frame 1s divided by this flatfield image care has to be taken not to reduce the S N of the science frames by underexposed flatfields One has to make sure that the S N of the flatfield images is much higher than that in the science frames including object signal in order to preserve their S N The effects just described are multiplicative effects i e they change the counts above back ground from the objects to be measured There are also however additive flat field effects which also produce non flat images but do not change the signal from the objects under study scattered light within the optics and fringing due to night sky emission lines are the two most important examples for additive flat field effects In practice it is often difficult to disentangle additive and multiplicative flat field effects and the inability to do this often limits the photo metric accuracy achievable The optimum way to get at least a global multiplicative flatfield 1s to observe a star during photometric conditions placed on the detector at regular intervals e g every 30 in both X and Y As this procedure is certainly not practicable during regular observing runs we plan to provide such flatfields for the most commonly used filters during the commissioning phase Then the flatfields taken by the observer during the run are only need to correct only the pixel to pixel sensiti
65. alf width for each focus test Plot the FWHM as a function of focus position Fit a parabola to the data Determine the minimum and thus optimum focus O O O O O O The MIDAS command regression table will be helpful if you put your measurements into a MIDAS table with the MIDAS table editor edit tab OMEGA2000 manual doc Functionality The following flow chart demonstrates the principal structure of the focus routine OMEG A200 FOCUS ROUTINE Setup Help Text parameters amp keywords lake Images with different tele scope focus positions Find Objects in Master Frame reti rm y position object classification Stellar Object Selection l erude selection of objects that were classitied as stellar 24 remove objects that ale too close to trame edge 4 remove objects that are saturated 4 vetined removal of remaining galaxies and cosmics Loop Over All Images determine x amp y FWHM of selected objects in image take average of all x amp y Fw HM in each Image Fit Parabola to PHM focus Data Points and Deterinine Minitnuin Display Results Focus Telescope Before the parabola is fitted the deviations between FWHM in X and Y are analysed Points who differ in FWHM between the two axis by more than 2 56 of the difference distribution are discarded in the fit Graphics output A total of 4 graphs is plotted during the object analysis process l 2
66. amera The screen at left 1s for LEIS SCOPE OP Cid ON uuu uu ER eds ee ein 146 List of Tables Table 1 Background levels in the most common observing bands 10 Table 2 Image rotation as a function of declination 15 Table 3 Conversion factor electrons per count EPC for each of the 32 channels 21 Table 4 Broad band filters 90 Table 5 Narrow band filters 90 Table 6 Exposure times for dome flats 92 Table 7 Exposure times for twilight flats 93 Table 8 Photometric zero points counts for zero magnitude 144 1 Introduction Observations at infra red wavelengths in the range between I and 2 5u are in principle very similar to CCD observations in the optical wavelength range Differences occur primarily due to the high background level in the IR and the different detector technology Both have direct consequences for the observing procedures and will be described in detail in this manual Once a raw image is obtained the data reduction and analysis for both wavelength regimes turn out to be identical This manual comes in three parts In the first part we describe IR observations and technology in general Sections 1 6 The second part describes the instrument and the control software Sections 7 11 Finally we give detailed instructions on how to use the OMEGA2000 cam era in Section 12 OMEGA2000 manual doc 2 Astronomical observations in the infra red region 2 1 Aim of the game OMEGA2000 is using one of the firs
67. ave command is not allowed to use the current next default filename but a special testfile name After the next save command the default filename is automatically reactivated also if there was an error or problem with the save command Multiple save orders in a single save command are treated as a single save command If option t is given without a filename the special name test is used else it uses the given filename But the testrile rrlename rS not used 1t the next save command is given with a filename To deactivate the just triggered next special test filename you might either just call next n without filename argument or next n filename where filename will be handled like above or next filename where filename will be handled like above Without any argument the command returns the next default and next test filename where the one which would be used at the next save command when save is given without a filename argument is marked as next The test filename shows you also the starting string of the saved files which are not queued to automatic storing to tape etc object EVDO USER syntax object text Sets text as object in the FITS header syntax object Prints the actual object observer EVpe USER syntax observer name Sets name as observer in the FITS header This name is used as password for the privileged commands syntax observer Prints th
68. camera control window The instrument 1s completely setup in the camera control window Here you select the filter the read out mode and the exposure times to name the most important You should use the filter macro to select your filter This 1s faster than turning the wheels individually Further more the macro automatically inserts also a blocking filter 1f necessary 9 5 2 Taking exposures An exposure is taken by pressing the READ button below centre in the camera control win dow Although this exposes the image it 1s only read into the memory of the instrument computer There you can use it to take a look at it on the real time display measure back ground level seeing etc there If you decide to keep the image you also have to decide on the mode on how to save the data e g as a FITS cube individual images stacked images by opening the SAVE OPTIONS window with a click of the right mouse button onto the save options button Once set you save the data by pressing the SAVE button Due to the double buffering an image may be saved while the next one 1s already been taken 9 5 3 Image inspection with the real time display The features of the real time display are described in detail in Section 9 3 2 Please note that you do not manipulate the raw data on disk with these operations 9 6 Saving data The data are stored on one of the disks of the instrument computer under the path you have specified under SavePath in the Op
69. chart for astrometric stars from M2000 OMEGA2000 manual doc January Elevation of astrometry fields M67 Astro 22h 90 80 Astro 05h didi Astro 02h 60 er Astro 13h 50 A a Astro 13h 40 30 Astro 18h 20 EM U 10 im 0 P O 18 00 19 00 20 00 21 00 22 00 23 00 0 00 1 00 2 00 3 00 4 00 5 00 6 00 UT moon April Elevation of astrometry fields M67 Astro 22h 90 80 Astro 05h Astro 02h 60 m M Astro 13h 50 A Astro 13h 40 B 30 Astro 18h 20 ET 10 0 19 00 20 00 21 00 22 00 23 00 0 00 1 00 2 00 3 00 4 00 5 00 UT moon Figure 65 Elevation plots for the astrometry fields January and April July Elevation of astrometry fields M67 Astro 22h 90 80 Astro 05h 70 a an Astro 02h 60 ut hg m l Astro 13h 50 A ur mm a e Astro 13h 40 A B 30 P wm o Astro 18h amp 20 u PE ky 4 10 x amp mw o ay 0 li 4 21 00 22 00 23 00 0 00 1 00 2 00 3 00 UT moon October Elevation of astrometry fields M67 Astro 22h 90 80 Astro 05h 70 Astro 02h 60 Astro 13h 50 A Astro 13h 40 B 30 e Si o A
70. cmd 02000 syne Semd o2000 Filter Pl Scmd o2000 sync OMEGA2000 manual doc 11 Trouble shooting From time to time it can happen that a process hangs Mostly you can simply kill the hanging process Some commands are prepared for this e kill read terminates a read command e kill telescope terminates any command to the telescope e kill wheel terminates any command for the filter wheels Type these commands in the interpreter window where you have started the GUI If you have any trouble with one of the instruments please report to Peter Bizenberger We will create a list of problems and if possible with solutions to help future observers avoiding the same trouble Problem You can t start the GUI solution Type cleanup before you start the GUI This program deletes all remaining software parts from a previous session Problem Data 1s useless counts between 0 and 65000 randomly distributed and the Abort but ton does not work Solution The fibers are connected wrong Problem Anything seems to work well but there are no stars Solution 1 Check the last button in the display window Problem Message can t allocate info page and you can t start the GUI Solution There 1s still a shared memory socket existing Delete in the tmp directory the shmsocket 12 Observing strategies 12 1 Minimizing overhead There are several sources for overhead during OMEGA2000 observations which critically determine th
71. cope control panel 9 3 6 Strip Chart Window The strip chart is a data base for images taken with the GUI The images are always displayed in a 128 x 128 pixel format To add an image to the strip chart you have to press the button send in the display window The number of displayed images depends of the size of the win dow If you increase the size of the window more images are displayed 9 4 The MIDAS sessions Figure 33 shows the desktops forseen for the operation of OMEGA2000 Three of the screens are for MIDAS sessions Their purpose is described in the following sections During launch of each of these you will be queeried for the current data directory The MIDAS sessions need to be run in the path where the data are Should you change this path later please then use the change dir path MIDAS command to set the path for the MIDAS session Do not use the N command cd path This will not work However pwd shows the current MIDAS path 9 4 1 Quicklook The green X terminal is the only session which is launched with a graphic and a display screen So this 1s the one to be used for any interactive work On the other hand it should not be blocked by launching a long observing session from here The following utilities need this window e focus test Section 13 1 page 51 e offsetting the telescope to pixel accuracy Section 13 8 page 73 e seeing measurement Section 13 7 page 73 This is MIDAS session 31 9 4 2
72. d cycle are saved either as single files s or integrated 1 in mem ory and saved as one file P8 reset Before exposure time 1s changed a reset 1s performed in that sense that the exposure time is set to the minimum time then two images are read out without saving them Then the exposure time is set to the desired value This should help eliminate the fifo overflow problem for the time being Use no reset to suppress this feature Functionality The desired filter and the read out mode have to be selected manually before this routine 1s called The exposure times for the number of specified images is calculated as follows The interval between minimum and maximum time is divided linearly or logarithmically into n segments If the exposure time 1s less than the minimum time allowed by the read out mode it is set to this minimum time Therefore if the exposure times are such that also fur ther 1mages are still below the minimum integration time several 1mages will result with minimum exposure time If no increase In exposure time is selected zero the exposure time is set to the maximum time specified in parameter 3 Note about darks We found out in September 2004 that the filter wheel 1s not absolutely light tight So in taking darks you should put the J low filter into wheel 1 blank in wheel 2 and e g H in wheel 3 13 2 Dome flats Function Call o2k domeflats ident lamp time coadd number save saturation Imag
73. disp gui control stripchart telgui tempcon shminfo rottab iniwin However a terminate does not necessarily mean that the process is able to catch the signal since the mechanism works passively sets a flag syntax kill name Send first a kill signal to a subprocess if name is from read save shell tele wheel filter lyot aperture optics If after timeout of currently 10 seconds the process has not been ended a kill 9 signal is send to the subprocess Additionally the PID entries and serial line flags are cleared and maybe some other flags which has to be reset lamp type USE Syntax damp Jon Olf in Out OELS Fiy OLIS CTI Controls the calibration lamp slider and the power of the calibration lamp last Ly oe USER syntax last destfile Returns the last filename of the last image saved and stores it also into destfile which by default is in directory CAMIMP mostly tmp the file geirsLstFile load type USER syntax load filename n Loads n FITS files into the shared memory Since the shared memory frame buffers are unsigned short integers the displayed values may be not correct You also have to switch the cycle type to reset read rr negative n add to shm logfile type USER syntax logfile filename If given sets filename as logfile name Otherwise prints the actual logfile name Format of the logfile UT FILENAME OBJECT RA DEC EQ AM ITIME COADDS WHEE
74. djacent image offset by re dome with a parallactic mount of Aa cos by an angle Ag This is illustrated in Figure 12 at right The rotation angle is Ad Axtan In case of OMEGA2000 this rotation will result in a misalignment of objects in two adjacent mosaic images If a stellar image at the border of the detector in X and in the centre in Y is assumed to be aligned in the two adjacent mosaic images an object in the upper lower corner would be misaligned by Ap 0 5 x 2048 x tan Ad 1024 x tan 15 4x tan pixels The following table provides the Ap values as a function of declination declination 0 10 20 30 40 so 60 70 80 n pixels x 0 x 8 x 1 7 x 2 6 x 3 8 x 5 5 x 22 x 12 6 x 26 0 x Table 2 Image rotation as a function of declination A differential effect in the same sense will also be created by dithering images see below 5 2 Background subtraction Traditionally the classical photometry consisted of measurements of the source In one aper ture and the neighbouring sky in another Then object and sky switched apertures and the pro cedure repeated With an FPA the sky still needs to be determined with sufficient accuracy to This is the difference between the angular distance of an object in the corner to an object in the centre calcu lated from the RA and DEC coordinates using spherical trigonometry and the distance between these two objects calculated from the X and Y co
75. e quested amount The set zero button zeroes the cumulative offsets S dx and S dy and the 0 0 button in the centre of the compass returns the telescope to this defined zero posi tion Object Files An object file can be given in the Object List window the obj extension is not necessary Objects can be selected with a single click and set with the set button Setting an object sends the object s coordinates to the RA and Dec windows These can then be sent to the telescope computer by clicking on move as described above A useful feature 1s that when an object 1s set the airmass panel will display the object s current airmass in graphical form though there is no obligation to actually move to the object See also Section 9 7 on page 45 for a description of the format of such an object catalogue 9 3 4 SAO Map Window The SAO map shows an area of sky centred on where the telescope 1s pointing The display includes all of the SAO stars in the vicinity colour coded as to spectral type Blue O B Green A F Yellow G Red K M Black unclassified where the size of the dot indicates relative brightness The dashed red square shows the size of the camera field of view A scale bar in the upper left corner of the image gives a scale reference Zooming the display in or out is done with the two arrow buttons in the upper right corner of the window Stars can be selected by clicking on the image with additional information SAO number spect
76. e actual observer s name optics type USER syntax optics wheel position pause type Moves camera optics wheel Without parameter all possible positions and the actual position are printed OmegaCass only optics is a background process and should have a sync after it when used in a macro USER syntax pause macro pipe type SUPER Syntax pipe nowezt list command pari Lpar2 ss Send command and parameters directly to the camera electonics No interpreation or limit checking is performed n owait just send command but do not wait for any answer l ist takes command as name for a command list file currently used in MIDI and OMEGA2000 pkginp LV De USER syntax pkginp h c devicename Starts read in process of GEIRS stream packages Accepts only devicenames starting with dev If no devicename is given the devicename has to be set via the environment PKGINPORT else you get an error should prevent accidential access of data ports just used Option h shows the command usage Option first reads all waiting data until a timeout of a a part of a second polpos type USER syntax polpos value Writes value at keyword POLPOS into the FITS header ptime Lypes ENG syntax ptime not available with the MAX 10um camera and with Omega MPIA electronics put type ENG syntax put i i f d j s offset value Stops any command execution only continue or kill is exec
77. e di rectly specified If they are nor located in the local directory the path has to be specified LABEL flatfield Note For the dark frame the descriptor ITIME has to specify the integration time The flatfield frame has to be normalized to 1 internal in PRG OMEGA pipeline prg contains a few internal parameters that are used as defaults and the online mode The corresponding keywords are specified in Section PIPELINE SETUP file path Has to contain the same path information as the file path keyword in the observing macros The keyword is needed for the online mode to allow communication to the current observing macros cal file Keyword containing the path and name of the default ASCII calibration file Calibration File In P calibration frames the name of an ASCII calibration file can be specified see above The calibration file has to fulfil the following format conventions IDENT calibration cal AUTHOR Rene Fassbender MPIA Heidelberg ENVIRONMENT MIDAS MODULE Calibration file KEYWORDS IR pipeline PURPOSE list name and path of calibration files to be used COMMENTS CONVENTIONS lines starting with are comments I Lines with calibration frame information have to start with a standard I identifier I BPM for the bad pixel mask DARK for the dark current frame I and FLAT or the filter name for the different flatfields
78. e observing efficiency e Telescope movement e Detector read out Telescope movements are especially important 1f extended objects are to be observed Here the overhead is determined mainly by the frequency with which sky fields are observed and how distant these are from the target In the case of sparse fields the dithering with short inte gration times and or low number of co adds also results in appreciable overhead The detector read out is currently limited to 1ir line interlaced mode in 32 channel mode For the time being also idle break should not be used as it results in images which are not properly flatfieldable The current default is thus idle wait In this situation the overhead can become substantial and it 1s thus mandatory to optimize the settings of integration times and number of co adds In general one should aim at low integration times and large number of co adds This minimizes the overhead due to the idle wait setting Integration times have however a lower bound as the images should be limited by background and not by de tector read noise Example If one takes images with 100sec integration time e g for narrow band imaging the following overhead without telescope movements have to be expected co add 1 elapse time is more than 200 sec due to idle wait dummy read and actual in tegration i e the efficiency 1s 50 co add 5 elapse time is somewhat larger than 600 sec so now the efficiency is 80 OM
79. e panel to the right with the OMEGA symbol or the MPIA logo respectively These but tons as do all the others hide pop up menus which can be opened by clicking on the small triangle above the symbol to show the following OMEGA specific tasks Quicklook terminal e ABEC br E A cin EN enin Bl met Guicklook x Pipeline A EnA Figure 33 The available screens to operate OMEGA2000 Clicking on a task opens an X terminal and starts the specific task e g the MIDAS session for the pipeline If you click onto the OMEGA2000 or the MPIA symbol without opening the pop up menu you directly start the OMEGA2000 GUI and the observing window respec tively Please note that in case of MIDAS sessions the X terminal will automatically be closed if you terminate the session OMEGA2000 manual doc The following setup proved to be useful Left hand screen GEIRS GUI and MIDAS session for pipeline reduction Right hand screen General DATspooler MIDAS sessions for Quicklook and Observing The MIDAS sessions start automatically after pressing the pull up buttons You have how ever to set the path in each session ch dir to where the data are save path set in GUI Currently it is best to start the desktops in the following sequence in order to not loose colours in those windows where they are desperately needed l GEIRS GUI 2 DAT spooler 3 MIDAS session for quicklook 4 pipeline 5 observing We
80. ect is 3600 seconds The integration time for the sky observations 1s not specified thus the same values as for the object are used The sky images are taken 20 arcmin North of the object The dither pattern starts at the default start position the descriptor POINT NO will contain the value 2 The name of the image catalogue created is M51 cat the descriptor IDENT of all images will contain M51 in J o2k sky point icat field A itime 1000 20 2 10 move 10 direction ALL object field A start pos 5355 pointing 8 offsets l Take 2 second exposures and add them up in memory to 20 second integrated 1m ages The total integration time for the object is 1000 seconds The total integration time for a single sky image is set to 10 seconds thus five 2 second exposures are co added in memory for the sky The sky images are taken 10 arcmin away from the object at 8 different positions The dither pattern starts at position 35 with non integer pixel offsets the descriptor POINT NO will contain the value 8 The name of the image catalogue created is field A cat the descriptor IDENT of all images will contain field A OMEGA2000 manual doc o2k sky point help Help text Parameters external Compared to the macro for normal observations three additional parameters have to be speci fied for observations of extended objects the distance and direction of the designated sky field from the object and the integration time for a single
81. either the readout process is preceded by re setting of the complete frame or the whole array is reset and read out simultaneously In the first case the elapsed time between resetting and reading out of the same pixel 1s equal to the resetting time of the full array The reset readout scheme is faster in the second case where each row 1s read out immediately after being reset Figure 17 As the video signal sampled after resetting contains the reset noise and reset bias this readout mode has only engineering purpose and is normally not available for observation ae mas ma MR Li NN IE one reset pulse for acomplete line 1 line 1 line 2 line 2 line 1024 line 1024 line Figure 17 The scheme of the reset level read reset read Non correlated Sampling or Single Correlated Read In the normal operation of the image sensor an integration time should elapse between the reset and the readout of the full frame so that some amount of photo signal could be collected The readout cycle of non correlated sampling implements this reset integration read scheme Figure 18 Now the resetting is separated from the readout process by integration which prevents the application of the fast reset method Since the exposure takes from the resetting of the first pixel actually the first line to the readout of it the resetting time of the full frame should be added to the integration time so as to obtain the total exposure time The integrated
82. emely good seeing and or some filters in the K band range narrow band K itself due to the high background We suggest that you use the H filter for focusing The focus will automatically be adjusted if you select another filter using the focus offsets measured under good seeing conditions Function call o2k focus ROSE start index focus step ima number itime total single action flag object number boxsize Remark o2k focus is an OMEGA2000 context command which calls the routine omega focus prg The focus routine can also be called without the context command in the following way O2K UTIL obs macros Focus omega focus Defaults root automatic take name from GUI start index 0001 only if not automatic focus no default prompt for estimated focus and step size 200 number 9 take 9 images itime 20 2 20 secs total integration 2 secs single integration action 0 1 take analyze and move focus show all graphics objects 40 search about 40 objects boxsize 18 total boxsize In arcsecs around objects for analysis Examples e o2k focus focus 23500 200 number 7 itime 10 1 Use 7 different focus positions centered around 23500 microns with offsets of 200 mi crons The total integration time per image 1s 10 seconds which consist of 10 co added 1 second exposures The image name in the GUI is used for the filenames e o2k focus foc H 4 24000 200 7 20 2 1 Use the seven images with names foc H0004
83. ent ongoing save cplats BPE USER syntax cplats Set number of co added plateaus in cycle types chop and chop d Max ONLY cre type USER syntax crep n subrep subrepskip Sets the cycle repeat count This defines the number of images that will be read after a read command The options subrep subrepskip are available for Midi for faster setup Instead using options you may use for Midi the coadds command Both are complementary and only one of the possibility is needed for correct setup If options not given there values will not be changed ctime type Syntax OMEGA2000 manual doc USER ctime time val Currently just returns the cycle time status ctype type syntax rst Perg pst delay type Syntax dir EvVvpe syntax display type syntax USER ctype name parameters Sets the cycle type Number availabele depends on the actual camera Valid cycle types for Omega2000 are Cure single correlated read like rr first full frame elc double correlated read like rrr first full frame BOE double correlated read like rrr mpia fast line BET laune p terlaced redd a doubleccorrelated read like err impia mer multiple endpoint sampling read like mep also called Fowler sampling parameter number of reads per edge NEE sample up the ramp read see also ramp parameter of reads on the ramp SUD XxX subarray mode in co
84. es are taken at the current telescope position The appropriate telescope position 1s 0h and 0 30 Put the dome at azimuth 90 i e do not use the flatfield screen The files will have the names specified in the instrument GUI Filter and read out mode have to be set manually before call Defaults identifier no default lamp no default has to be I to 5 In case of 5 also the level 1s needed time no default coadds I Images l save s ingle saturation 20000 Examples o2k domeflats dome H 5 1 3 Takes one image in a single exposure with lamp 5 at level I Watt Exposure time is 3 sec o2k domeflats dome H 5 1 3 5 i same as above but 5 images are added up in memory and saved as a integrated 1m age o2k domeflats help Help text Parameters external P1 ident Object name for the FITS header Use quotes if text contains blanks PZ PS lamp The lamps are numbered to 5 decreasing brightness Only lamp 5 can be adjusted in its level from to 10 W Give level in addition to lamp number in this case like 5 1 P4 integration time The exposure of a single frame in seconds PS P6 E Po OMEGA2000 manual doc coadds Number of exposure repetitions in one read cycle images Number of read cycles to be executed save mode If integrated 1 is selected all exposures taken in a single read cycle coadds are summed up in memory and stored as a single file on disk In single s mode the ex
85. es prg The routine can also be called without the context com mand in the following way O2K UTIL obs macros calibration series Defaults ident no default use quotes if containing blanks time no default coadds l one Image per read cycle number 5 take 5 read cycles spacing lin exposure times increase linearly save S save all images of a read cycle as single frames Examples e o2k calser dark 300 Takes 5 dark exposures with exposure times from minimum available time to a maxi mum of 300sec The exposure time increases linearly from exposure to exposure e o2k calser flat H 2 10 3 log Flatfield with 3 integrations added in memory Five images taken Logarithmically increasing exposure times between 2 and 10 sec e o2k calser help Shows help text Parameter explanation External command line parameters Pl identifier P2 P3 time or min time max time Longest exposure time in series sec starting with 0 or minimum and maximum integration time between which exposures will be taken P4 coadds number of exposures to be taken in a read cycle OMEGA2000 manual doc P5 number Number of images read cycles to be taken This defines the intervals in exposure time between minimum and maximum P6 spacing Exposure times may be increased linearly lin logarithmically log or not at all zero In the latter case the exposure time is set to time P save mode The images of a rea
86. escope coordinates syntax tele time synchronizes telescope and computer time syntax tele get allpositions Requests tele pos and tele focus syntax tele nod main offset Moves the telescope to the desired nodding position UKIRT only syntax tele Print telescope name and TECS status telgui type USER syntax telgui x xserver f font Starts a graphical user interface GUI to the telescope x X terminal or X server to connect lt f font Tor menus and DUETSNS tempcontrol type USER syntax tempc on x xserver f font starts temperature controller Useful for Max only x where to open the window e g xt28 0 f font family e g lucida temphistory type USER syntax temph file x timel time2 f timel y templ temp2 d xserver see tempplot tempplot type USER syntax tempp file x timel time2 f time y templ temp2 d xserver Plots temperature log file created by tempcon X axis minutes Y axis degrees Kelvin x timel time2 begin end time of the graph f time start time of the graph y templ temp2 lower upper temperature limit of the graph d where to open the window e g xt28 0 This window will NOT be killed when the software is shut down using the quit command test EVDE ENG syntax test std med var q 4 r nl n2 executes array electronics tests and appends the result to the file Tehiplest dleg either in CAMIMP normally tmp or
87. et to position start pos 1 before nominal operation offset to the desired starting position 1s resumed This is convenient if the previous sequence was aborted and the field had to acquisitioned again POLNEGO Identification integer for the descriptor POINT NO Can be used for easier data iden tification offsets OMEGA2000 manual doc Flag for dither offset mode offsets 0 gt the offsets will integer multiples of the pixel scale offsets 1 gt offsets in units of 1 3 of a pixel are used for the dither pattern This facili tates the use of drizzle to obtain super resolution in case of very good seeing offset name gt the offsets are specified in a file with this name This file is a plain ASCII file with AX AY in arcsec per line no blanks allowed The first line is a comment and exactly 20 offsets are required The offsets are relative to the previous position The standard repetition offsets see be low are used also in this case This file has to be located in the current path The standard mode should be integer offsets because it facilitates a later summation of several 1mages by appropriate xy shifting internal The keyword file path defined as the first keyword in the PRG contains the path information for the pipeline auxiliary files In online mode the pipeline searches this path for all relevant information Dither Pattern The standard dither pattern 1s shown in Figure 41 below The actual pattern co
88. f you want to start the macro test mac in HOME macros then enter macro macros test mac It is posible to write comments into your macros using a semi colon The lines are truncated at the point where the first was found before the line is executed TE the first character n a dine zs a LL thbre Jane will not be executed ENG median r aw stdout or stderr nt n2 xl vi 2792 Calculates the median of images nl through n2 Default is all images Ihe options starting with have to be the first parameters before the images nX or the areas xX Optional you might using the subarray xl yl x2 y2 parameter only Attention using the wrong area in subarray images the behaviour is unspecified msio EPE It appends the result to the file SCAMTMP median log where additionally the integration time sec is written in front of the median Options stdout stderr delivers to the according data stream only the resulting value numbers r aw does not take the single image resulting normally from the read out mode but all single frames of the image for the calculation Example median of 2 images in the buffer median 1 2004 median 2 2003 ave medians 2003 50 Example median raw of 2 double corr images in the buffer median 1 1004 2007 median 2 1003 2001 ave medians 1003 50 2004 00 where with the stdout or stderr only the resulting 2 00 59 90 GE 1003 50 2004 00 is de
89. fferent detec tor locations the results can be combined into one output frame with a larger number of data points This can be achieved be editing the file 02K UTIL obs macros Tilt master tilt prg Which combines the results from two tilt measurements Before it can be used a master tilt frame e g mas ter tilt bdf has to be created Functionality The tilt routine is determining the local focus position according to the algorithm described in 1 without the telescope and instrument parts The local deviation of the focus from the av erage over the field of view is plotted in an output frame OMEGA2000 manual doc 13 6 Taking dithered science frames Two different observing macros are provided One for dithered observations of sparse fields with sky determination from the science frames and a second macro for alternate ob servations of an extended object and a designated sky field 13 6 1 Survey observations Function Call o2k dither icatalog itime tot pointing tot single single object start pos tel pos pointing offsets Remark The actual routine is called dither_pointing prg and can also be called by Ga O2K UTIL obs macros dither pointing Defaults icatalog no default itime no default object identitfier no default start pos 1 PREV start at first dither position telescope at n 1 pointing 1 pointing identification number for header offsets 0 use pixel integer offsets for the dither pattern Exa
90. file can be associated with a va riety of different functions such as telescope moves completion of a read e Savepath Macropath and Objectpath tell the GUI where to save data and where to look for macro and object files e Logfile specifies where the log file is kept Note that the logfile path needs to be re entered each time the GUI is restarted and the other path parameters should be che cked Below the drop down menus various fields display the status of the camera and allow the setup to be changed Baffle shield To suppress background radiation at long wavelengths the baffle may be put into the de ployed position see Section 7 4 OMEGA2000 manual doc Filter wheels While the control panel allows for addressing each wheel separately all requests for filters should be made from the wheel macro panel where all standard observing configurations are available The individual filter wheels should say moving as the wheels are being reposi tioned then display the actual position filter name open or blank when set Read setup Mode The different read modes available are described in detail in Section 3 2 For standard broad band observing this should normally be left at double correlated read called o2dcr or rrr IT s is the integration time in seconds Note that the minimum exposure time with Omega2000 is 0 8 seconds except for mode lir where it is 1 6sec Keep this in mind when doing broad band observations u
91. frames are set to median 2sigma median 5sigma The mod elled sky will not be saved all calibrations are done at the beginning sup press any screen output Use the ASCII file disk a o2k cal file cal to read in the paths and names of the calibration files o2k pipeline Lcabpeobs B framess2 mode 0 0 Sium 2 Do only single image reduction of the image catalogue obs B cat Use the minimum mode with averaging of the 2 smallest values and sky determina tion from 5 frames 2 on either side The calibration frames are read in from the default calibration file according to the filter used o2k pipeline icat automatic frames 2 mode 1 sum 9 0 2 kappa sum 8 flatfield norm flat fits bpm std fits disk a o2k dark frame fits Use the current image catalogue of the ongoing observations The sky is de termined from 2 2 1 5 frames in the fast median mode The reference im age for the summation is computed every 9 images single image reduction and summation is done and the final cosmics cleaned sum image as well as the real uncorrected sum image and the difference image are saved The cosmics clipping parameter is set to 8 sigma above the median The flatfield norm flat fits and the bad pixel mask bpm std fits are in the local direc tory the dark current frame is stored in disk a o2k dark frame fits o2k pipeline help Shows help text Parameters external command line parameters E 2 image catalogue Name and
92. h the name and path of the latest 1mage after every integration e With each new telescope movement the time the offset and the dither number are written into a log file tel pos date log in the current directory The date in the file name is the date and time the MIDAS procedure was started 13 7 Measuring the seeing o2k seeing zoom default no zoom To measure the seeing in a frame proceed as follows e Select the quicklook desktop e Load a flat fielded image into the display at appropriate scale e Execute o2k seeing e Selecta region in the display with the crosshair cursor left mouse click o Region is displayed in zoom window e Adjust cursor box size in zoom window with arrow keys o Hint hitting 1 9 speeds up cursor movement Mark stellar objects with left mouse button To go back to the display window click right mouse button in zoom window Select next region Exit with right mouse click from display window The seeing values are appended to file Seeing log in the current directory The individual measurements for the current call are stored in table seeing tbl which 1s overwritten with each new call to this procedure saturated images are skipped in calculating the seeing 13 8 Pixel accurate alignment of the telescope o2k offset dest X dest y To offset the telescope in order to put a star onto a given pixel proceed as follows e Select the quicklook desktop e Load a flat fielded acquisition image into the disp
93. here 9 7 Object catalogues You can create your own object list in the following format Object name Alpha Delta Equinox pm A pm D mag Comment Example HD 225023 0 00011 9 33232274 09 LOS 00 000 002 004 65 96375 1 97 G158 22 020227 12 0 7227 232 2 1 2 o I Fr 72 HD 1 L 913223 ii 8238222 0 193907095 20231 7202927098 HD 2029 923120222 20509 301 0 E32 Du QOO ITO OD D V Lr seo GL So 2338320720 oed 950 er es HD Lecchi 23 2500 20 95 2392412 995 0 01990109 900041 0 0307 TA 9 T s 2 Note The line character 1s used as a separator between fields If you don t want to put in numbers in some fields you still have to use a character as a place holder Important e Ifyou have negative declination less than one degree then you must place the negative sign before the minutes e g 0 13 45 6 The required fields are Name Alpha Delta Equinox The optional fields are pm A pm D mag Comment pm A and pm D are in units of arcsec century All object list files must have the extension obj Some useful catalogues focus fields etc are found under disk a o2k OBJECT CATs The current catalogues are focus fields astro fields faintstd arnica Please note For the time being the equinox in the catalogue and the one set in the telescope GUI have to be the same Otherwise the telescope will not position properly OMEGA2000 manual doc 10 Macros You can prepare macro files in advance to car
94. icates the field of view of OMEGA2000 Focus at 1h a J2000 0 55 12 33 8 J2000 24 55 05 sy b 4 e c B a e w Pd L jd e Figure 50 Focus field at RA Ih A bright star in the neighbourhood produces a luminous arc in the field of view NGC 1647 a J2000 4 45 51 52 8 J2000 19 00 30 Figure 51 Focus field at RA 5h NGC 1647 OMEGA2000 manual doc a J2000 8 51 15 79 8 72000 11 49 8 M 67 s r z a Pr t ri Es E J r r Z1 3 d a 4 m a E p n T a tras i L a 2 ED dB u a d w 7 E Ze U 4 f T m P E z a 1 a ar ar T o g i i L a 1 diis E e E T a e ie oa a p i f O 4 m e L et E I eo ie Mead 2 Se Nee j t bt I dat t Ad di E a as f oa E s u LE i bi a M jr 1 a E Ja T i E eS K de u 1 m z ooa U E n as 2 z ER m 2 a F sj 2 ate F L FE T Fr E a a i gi T a L s s u Y k E i ie 1 a d s ka lay NS Lo 7 z 3 a j o x s T n i m F a a i h a k e a p i 3 a B mL 4 4 z 1 gt gt a P a 1 1 LJ
95. index e g focus001 bdf or foc_K097 bdf The relevant images have to have consecutive indices The conversion can be done be editing the file 502K UTIL obs macros Tilt make bdf prg e The internal parameters for pixel saturation and the stellar cutoff can be adjusted to opti mize the output quality Function Call The function call o2k tilt will prompt the relevant parameters estimated focus value number of images step size name of first image in the above format name of master image image with the estimated focus in the above name format number of objects and box size Note The use of the default value for box size 1s suggested it 1s specified in pixels The de fault for the number of objects 1s 200 which is the maximum the search routine can handle Example o2k tilt typical inputs at the prompt would be 24000 gt estimated focus 7 or 9 gt number of images 200 gt step size focus001 name of first image with full name focus001 bdf focus004 name of masterframe if 7 images were used default object number default gt box size e The results are stored in the output frame tilt frame bdf which contains the local fo cus deviation compared to the average focus over the field of view The average is set to the arbitrary value 100 000 the deviations are given 1n microns Appropriate cuts are thus 99900 100100 If focus series at different telescope positions exist 1 e the stars are at di
96. ingle image We recom mend this readout mode particularly for broadband imaging where you reach the background limit quickly and can thus accept the higher read noise 3 2 3 Multiple end point sampling jj eos Figure 9 Read out mode multiple end point sampling This mode is not implemented in OMEGA2000 This variant of Double Correlated Sampling is also known as Fowler sampling see Fowler and Gatley 1991 The array 1s read multiple times after the initial reset and before the final reset This scheme can reduce the read noise substantially theoretically by a factor JN In practice however amplifier glow and other effects limit the This mode is recommended in low background applications 3 2 4 Sample up the ramp Figure 10 Readout mode sample up the ramp This mode is not implemented in OMEGA2000 This readout scheme also reduces the effective read noise since the pixel voltage 1s sampled N times at equal intervals during the integration The total signal comes from a linear fit through the measurements ctype ramp or from saving the differences between adjacent reads ctype speckle The latter 1s used for speckle interferometry since the observer can save these adjacent differences as separate frames each of which is a rapid exposure on the sky Warn ing Be careful not to saturate the total signal in this mode This can happen easily when ob serving lunar occultations for example You may have to settle for a
97. ion of the current wheel combination relative focus for all filters which are configured via CHKFOCUS correction in the wheelN instrument configuration files but does NOT change the OD off state Ive it takes the current focus position as being correct for the current filter combination Focus correction is always done relative to the last filter combination which was saved at the last filter correction action Attention xserver Evy pe Syntax Focus settings outside the wheel focus correction automatism does not influence the correct behaviour ot the relative focus corrections as long as no combination of wheel filter changes AND manual focus changes are done during the state wheel focus off to switch relative wheel focus correction on when wheel changes AND manual focus settings were done in state off use the com mand wheel focus new to discard the saved last relative focus correction information and to update it with the current focus initialisation of wheels does not change the focus but activates the focus correction for the next wheel usage for initialisation the focus correction is still correct if no change of the focus logic were made USER xserver xserver Set default X display X server name for stripchart and for the slave display OMEGA2000 manual doc Appendix 7 Recommended focus fields Finding charts are from red DSS II plates and are 20 on a side The dashed square ind
98. is in charge of the following tasks e filter wheel movements e deploying the movable baffle e monitoring of various temperatures in the instrument and pressure in the dewar An example of the latter is given below in Figure 31 see also graph on page 35 Dewar cool down 300 Filter Box 250 Motor e Detector Plate g Cold Plate o 200 Outer Shield 3 150 100 0 2 4 6 8 10 12 14 16 18 20 22 0 delta time h Figure 31 Monitoring the dewar temperatures during cool down OMEGA2000 manual doc 8 The 3 5m telescope Although the telescope system is pretty much independent from the instrument control there are some parameters that must be set correctly within the telescope software in order for OMEGA2000 to work properly Coordinate system The 3 5m telescope knows three different software coordinate systems e AD is the Right Ascension Declination Here an offset in RA specifies the rotation of the hour axis in arcsec e XY is the detector system Offsets in X are the actual movement of the objects on the detector i e the cos d is taken into account AX Aa l5 cos Please note that you will not come back to the origin if you move the telescope e g in a rectangle of equal sides due to the field rotation described in Section 5 1 The ob serving utilities use this coordinate system e UV is the rotated detector system Here any rotation of the mounting fla
99. lay e o2k offset dest x dest y O Coordinates are in pixels e Mark star whose position is used for alignment with cursor box o This determines the star s centroid via center gauss e Offset coordinates are displayed e Execute by giving a if okay or h if you need to abort or adjust e Check via new acquisition frame optional The telescope pointing is accurate to about 10 If you require higher accuracy you need to calculate the expected position of a reference star in your field e g from one of the following catalogues and the desired pointing center e USNO http www nofs navy mil data fchpix e M2000 http www obs u bordeaux1 fr public astro CSO equipe JF M2000 m2000 htm e UCAC2 http ad usno navy mil ucac Due to the excellent image quality no image distorsion needs to be taken into account OMEGA2000 manual doc 13 9 Relative calibration of survey fields ozk telc al Identifier e dit ndit Relative calibration of an OMEGA2000 mosaic of 1 square degree blue squares in illustra tion below by taking 3x3 pointings red squares on intersection of the mosaic exposures Telescope is assumed to be positioned in centre of 4x4 mosaic O at start Filter and read out mode have to be set before calling this routine 13 10 Determining bad pixel mask and dark frame The mask for bad pixels and the dark frames dark signal pixel sec are needed for the pipe line reduction Both are conveniently obtained from a
100. le instrangle Without parameter the actual field of view angle relative to NSEW will be printed counter clockwise The complete cassegrain angle would be casspos actual cass angle cassoff tinstrangletgiven fratio This value should be written into the FITS headers as CASSPOS USER reame trme l estdout estderr olfifset see miubtriple sec Set the integration time time in seconds Without time argument it prints the actual Integration time Status If the one of the options stdout or stderr is given the status value is additionally printed to the according output stream The options o and m are specifying adjustment and offset val ues which are valid and used until the value s are set back to 0 0 according to the formula used itime m ultiple adjustment o ffset exar 69 04030 adds a constant offset of 0 030 seconds esos m 5020 adjusts itime to a multiple of 0 020 seconds 50Hz multiple adjusted itime always gt given itime Attention These values can be configured by the staff via the envi ronment variables CAMITIME MULT and CAMITIME PLUS else the default value is 0 0 or 0 0 but may be always be changed via the itime command by the user USER itype type Set the integration type as IWR or ITR Without type it prints the actual integration type USER kill name Sends a software terminate flag to a subprocess if name is from display satcheck engwin s
101. livered to the according datastream ENG syntax msio drive command 3000 Sends command to motor drive drive prvileged command This command is used for test with the wheels command uses the syntax of the motor drives e g move 10 moves the motor 10 steps move 20 moves the motor 20 steps pos 9000 moves the motor to the absolute position 9000 ver p returns the absolute position in motor steps drive 1 lower filter 22 Lor SGOp 3 upper filter 4 aperture OmegaCass commands e g po status of switches and home switch ET absolut position or position since power on D3000 36 SER moves motor 3000 steps or to absolute position and waits on end of execution drive T Optics 2 DOl or ism So yor JT F lter 2 x Sealer 6 aperture msio always waits for a reponse from motor next Lype OMEGA2000 manual doc USER syntax next t or n filename Sets filename as the default filename This filename is used when no filename is given with the save command Auto numbering A filename with an alpha char at the end basename will automatically be extended with 4 digits where first the current save path is looked up for any files which contain any of the GEIRS extensions with the basename and 4 digits at the end Then the next free digits count is added to the given basename and used as next filename Option t with or without a filename tells the system that the next s
102. ll Default no switches abort everything except save and backup On read abort the file geirsLstAbort is written to SCAMTMP tmp and contains date and time of abort alarm type USER syntax alarm sound volume Play General Error sound You may enter a sound file but this file must be located in SCAMHOME SOUNDS volume range is from 1 to 100 aperture Gy pes USER syntax aperture name Move the aperture wheel to position name The named positions are defined in the file SCAMINFO wheel ext If called without a parameter aperture prints all possible aperture positions and the actual one The wheel and ext depends on the actual camera system aperture is a background process and should have a sync OMEGA2000 manual doc after it when used in a macro area EYDES USER syntax area x1 y1 x2 y2 Sets the area of the image that is used for all save operations except d dump file Xlwvlt Lower lert corner x2 V2 Upper Tight corner area without parameters returns the actual save area autosave type USER Syntaxe aurosave yes on no yort es f nm sL md e mL Pep 9s d Enables disables automatic save operation after during a read Ihe switches are explained with the save command Without parameter the actual autosave status is printed backup type USER syntax backup path device Copies all files in the directory path to device
103. lternate representation of the double correlated read Correlated Double Sampling with Fast Reset The correlated double sampling can also be implemented with the fast reset scheme This means that the reset and the readout of the reset level are carried out simultaneously and fol lowed by the integration and the readout of the integrated video signal Figure 21 The result frame is provided by subtraction of the reset level from the integrated signal Since the whole array is clocked only two times once for the reset with the first readout and once for the sec ond readout the efficiency of this readout scheme 1s 50 for the minimal integration time The CDS with fast reset is planned to be one of the optional readout modes for scientific op eration Reset Read Reset Read Integration Read line t line 1024 line 1024 line line 1024 line Figure 21 The scheme of correlated double sampling with fast reset reset read read row time Figure 22 Alternate representation of the double correlated read with fast reset Line interlaced Read It is possible to extend the CDS with fast reset in such a way that the readout of the integrated signal in each line is followed by a line reset and a readout of the reset values in that line As a OMEGA2000 manual doc result a complete frame is reset and its reset level is read out for the next cycle while the ar ray is clocked line by line to obtain the in
104. mag HIERARCH CAHA TEL POS AZ END 142 50 telescope azimuth at end deg HIERARCH CAHA TEL POS EL END 62 80 telescope elevation at end deg HIERARCH CAHA TEL POS HA END 29 646955 01 58 35 3 HA deg at end Appendix 6 Complete list of macros The following macro commands are available in GEIRS some are not applicable to OMEGA2000 abort alarm aperture area autosave backup batching buffers cassoff casspos Gu chopper clobber coadds continue Gor trolls counter cplats crep ctime ctype delay OLE display engstatus engwindow exit filter fts get Gul help history hpmove idlemode init iniwindow interactive instrangle itime itype kahl lamp last load logfile ls ls iR geje macro median msio next object observer Optics pause pipe pkginp polpos ptime put pwd quit read repeat resets rmode rottab rtime saad satcheck save set shminfo Sky sleep sndwin sound status Stripchart subwin Sync system to el EZ tdebug te lescope telgui tempcontrol temphistory tempplot test trigger userstatus verbose version wheel xserver abort EYP USER syntaxi abort r k tada EMW Test Er est Fb Aborts read and macro execution r abort read only d abort Save ol data only I aport macro only 5 Orb Sync Only La aDOrE teste Only a abort all processes above here epe abort backup k 4 special option to kill read after waiting seconds dTlte2 First tries smooth kill via catchable signal then urge the ki
105. mal user command ENG engineering command not needed for standard operations SUPER system safety critical commands A password is required to use such a command the observer s name has to be the password Parameters in are optional List of exclusive values are enclosed in help x starts a HTML browser and loads the camera software documentation USER RESTOFCM Prints the command history Repeats the last command abc Repeats the last command that starts with abc ENG hpmove x y Move HP plotter idlemode type USER syntax idlemode action threshold Selects the used idlemode default normally auto with 2secs Without parameters it shows the idlemode status Option action break interrupts idle clocking to start the next read immediately wait goes seamless from idle clocking Eo CLOCKiInG or read out auto uses a integ time threshold to decide for one of the above actions Option threshold float value of integration time Below that value idlemode wait is used else idlemode break init type USER syntax init camera name o optics s status m status t status Initialize the camera Valid camera names and optics are defined in CAMHOME src camera h If no name is given the current settings are used and checked camera BlueMagic BlackMagic Max128 Max256 0O0megaPrime IRL OmegaPrime MPIA OmegaCass IRL OmegaCass MPIA o optics wide high very side d
106. minimum exposure time for this camera DISCLAIMER Every such document must have the obligatory disclaimer preferably in unreadably small print so here is mine Every attempt has been made to provide accurate finding charts positions and magnitudes for these standard stars As in life however there are no guarantees so use this information at your own risk FS 11 FS 14 FS 13 FS 16 FS 15 FS 18 FS 20 A IN rr T REA FS 26
107. mount of the telescope 15 Figure 13 Determination of sky background from dithered science frames 16 Figure 14 OMEGA2000 on the frontring cut away CAD dratnsg 20 Figure 15 Quantum efficiency of a HAWAII 2 detector Finger 2002 as a function of wavelength left Variation of quantum efficiecy across the detector for FPA 437 right m 20 Figure 16 Quadrant and channel layout for the HAWAII 2 detector 21 Figure 17 The scheme of the reset level read reset read 22 Figure 18 The scheme of non correlated sampling reset read 27 Figure 19 The scheme of correlated double sampling reset read read 23 Figure 20 Alternate representation of the double correlated read 23 Figure 21 The scheme of correlated double sampling with fast reset reset read read 23 Figure 22 Alternate representation of the double correlated read with fast reset 23 Figure 23 The scheme or the Ime interlaced Tead anni 24 Figure 24 Alternate representation of the line interlaced read 24 Figure 25 The scheme of the multiple end point read
108. mpirical values for OMEGA2000 can be given yet For the broad band filters the following table gives the approximate levels to be expected to be updated Table 1 Background levels in the most common observing bands 3 Detecting photons 3 1 Focal plane arrays for the infra red Infrared focal plane arrays FPA differ from visible wavelength CCDs in requiring special semiconductors with a smaller energy difference between the valence and conduction bands Typical materials include indium antimonide InSb platinum silicide PtSi and mercury cadmium telluride HgCdTe OMEGA2000 s detector is a HgCdTe device The figure below contains a schematic drawing of the Rockwell NICMOS3 infrared array in OMEGA2000 photons sapphire HgCdTe detector indium bumps Figure 4 Schematic structure of a HgCdTe HAWAII detector Photoelectrons are collected in the detector material and read out using a multiplexer Because silicon multiplexer technology is much more mature HgCdTe and InSb arrays are hybridized This means that the detector material is cold welded to a silicon multiplexer using a series of small indium bumps The actual HgCdTe detector material is grown on a sapphire substrate for mechanical strength This hybrid arrangement has the benefit of lower crosstalk and less blooming and streaking compared with visible wavelength CCD s Another significant advan tage of the hybrid is that it permits non destructive readouts
109. mples o2k dither QSO H 3600 30 5 quasar at z 1 5 4 Take 5 second exposures and add them up in memory to 30 second integrated 1mages The total integration time 1s 3600 seconds The dither pattern starts at the default start position the descriptor POINT NO will contain the value 4 The name of the image catalogue created is QSO H cat the descriptor IDENT of all images will contain quasar at z 1 5 o2k dither icat field A itime 1000 20 2 object field A start pos 35 AQ pointing 8 offsets l Take 2 second exposures and add them up in memory to 20 second integrated 1mages The total integration time 1s 1000 seconds The dither pattern continues at position 35 with non integer dither offsets Telescope is at the acquisition position The descriptor POINT NO will contain the value 8 The name of the image catalogue created s A field cat the descriptor IDENT of all images will contain field A o2k dither help Help text Parameters external EX EZ Po P4 P3 P6 1catalog Name of image catalogue that contains a list of all taken images The name of the m age catalogue is automatically passed on to the pipeline and can be used for online data reduction If no online or further pipeline reduction is desired this parameter is just a dummy For online reductions the icatalog parameter should by specified with distinct names to prevent pipeline reduction of the wrong data set itime tot_pointing t
110. n age n Fuel Sl Value 14 2 3 Summation of dithered images Pixel Column ih Word Coordinates Replace Comi by Wedin Value Prepare Sum mation Find Objects Load Stack Statistics Object Positions RF Obsetvi ng Position Real Frame Offets TWatinaliza tian LLDDLILIL sum Stack lmages L N Med lan d o deis Fixel Value Go to Neat Pixel Final hlaster Sum e Cot the Pinal Master Sum Frame 79 Add the Sum of Stack Images ta the Master Sum OMEGA2000 manual doc 14 3 Examples of pipeline results 14 3 1 Images taken with o2k dither La A gt a 5 NO U L NN Dm a E Fi Figure 45 Pipeline result for a sparsely populated field This is the sum of 25 exposures in H The single exposure was 3sec 20 exposures were coad ded in memory Thus the total integration time 1s 25 min The 56 limiting magnitude as de termined from 2MASS stars and the background noise is 20 8 2 aperture seeing 0 9 Note the over corrected background around objects extended more than the dither amplitude This 1s due to the sky being determined from images of the same field 14 3 2 Images taken with o2k sky point Figure 46 Pipeline result for an image of an extended object NGC7331 in the H band For this image 8 exposures of 30sec exposure time 5sec and 6 co adds in memory were used The sky was taken 20 north of the galaxy For extended objects the sky m
111. nd Detectors M Iye and A F M Moorwood International Society for Optical Engineering 4008 1305 Beckett M G 1995 High resolution infrared imaging Institute of Astronomy and Caven dish Laboratory Wolfson College Cambridge University of Cambridge 120 Cox A N Ed 2000 Allen s Astrophysical Quantities New York Springer Verlag Fa bender R 2003 Commissioning of the near IR camera OMEGA2000 and development of a pipeline reduction system Max Planck Institut f r Astronomie Heidelberg Ru precht Karls Universitat 95 Finger G 2002 Test report on HgCdTe infrared focal plane arrays Garchung European southern Obervatory 18 Fowler A M and I Gatley 1991 Noise reduction strategy for hybrid IR focal plane arrays Noise reduction strategy for hybrid IR focal plane arrays T S Jayadev 1541 127 133 Kovacs Z 2005 Testing and commissioning of the OMEGA2000 detector Max Planck Institut f r Astronomie Heidelberg Ruprecht Karls Universit t Leinert C et al 1998 The 1997 reference of diffuse night sky brightness Astronomy and Astrophysics Supplement Series 127 1 99 Maihara T et al 1993 Observations of the OH airglow emission Publications of the Astronomical Society of the Pacific 105 940 944 Ramsay S K C M Mountain and T R Geballe 1992 Non thermal emission in the at mosphere above Mauna Kea Monthly Notices of the Royal Astronomical Society 259 751 760 Rapapor
112. nder high background conditions or when observing bright objects the array can easily saturate during these 0 8 seconds of dead time while the array is resetting cycT s is the total time for one read cycle in seconds Read Resets is the number of reads and resets executed in the current read cycle ieff elapse time gives the observing efficiency as the ratio of integration time to elapse time seff elapse time gives the system efficiency as the ratio of time for read out to elapse time Repeat is the number of images N with the specified exposure time T which will be taken each time a read is executed read cycle The total exposure time will then be N x T seconds The maximum number of images depends on the setup of the computer memory It is cur rently 23 images The current sequence number of the reads is displayed to the left READ button see below Endless may be pressed to start an endless loop of reads The images are read out with the current integration time and dumped to the display but are not saved This is useful for positioning the telescope before e g starting a macro Read The read button executes a read using the current exposure time and number of repeats On completion of a read the images are not saved unless autosave is selected under the save option Save The save button saves the most recent image s obtained using the currently defined save options Filename The name of the next file to be
113. neighbouring good pixels To facilitate this we provide a bad pixel mask whose pixel values of 0 indicate good those of 1 bad pixels The mask was derived from the dark current analysis by an appropriate cut in the goodness of fit of the linear relation between dark current and exposure time The same was done for a series of dome flats Both series were analyzed with the MIDAS procedure bias extrapolation described on page 74 6 5 Linearity Exposing a detector pixel to twice the number of photons should result in an exactly dupli cated recorded signal This is however not strictly true in general Each pixel may behave slightly non linear We have measured the linearity of FPA 77 Using the thermal emission of the front cover and controlling the exposure level via the exact exposure time we have fitted the signal as a function of exposure time for each pixel with a parabola see MIDAS procedure bias extrapolation on page 74 For each coefficient we have created an image whose pixel value specifies the coefficient for this pixel Using these frames any non linearity can be investigated Details are given in Appendix 3 We have not yet done this for different filters Thus we cannot comment on an wavelength dependence of the linearity non linearity 6 6 Astrometric calibration The image scale in arcsec pixel and the image distortion of the camera has been measured during the commissioning runs see Sections 7 1 and 0 These should
114. nge is also automatically taken into account This is not relevant for OMEGA2000 which 1s mounted at a permanently fixed angle of 0 on the front ring For the observations you should select the XY system The MIDAS procedures do this auto matically Coordinate zero point For object acquisition and tracking the telescope software makes use of a pointing model which takes into account any misalignment of the telescope s axes as well as flexure in the telescope structure The Ot order parameter of the pointing model is the zero point offset for both axes of the telescope This value should be set by Calar Alto staff who also select the appropriate pointing model Should the zero point not be correct you will not find your ob jects Here is the correct value QKORPAR T NULL 163 3 QKORPAR D NULL 0 To check the pointing accuracy use one of the stars 1n the astrometric fields provided in Appendix 8 The tables with the positional data from the M2000 and the UCAC2 catalogues are to be found on fire35 in directory disk a o2k MANUAL Focus position The nominal focus position for OMEGA2000 is 22700 T 10 C The temperature coeffi cient is 165u C Make sure the focus automatic which compensates thermal expansion due to temperature variations as well as flexure is activated during your observations Tip tilt The four Serrurier trusses can be set individually to incline the front ring For OMEGA2000 all four focus readings ha
115. nsert tape into drive on fire35 o cd disk a o2k tape listings o SPM fitslist OMEGA2000 manual doc Answer the questions and give OMEGA2k format as format file Please delete the listings you created there 14 Online data reduction pipeline General Remarks e The OMEGA2000 pipeline is a MIDAS application program written in C which is called from a MIDAS procedures Thus an active MIDAS session 1s required and the context omega2k ctx has to be set for the definition of the utility short cut com mands o2k command e Several pipeline parts use the environment variable O2K_UTIL which points to the directory o2k utilities All paths are defined relative from this top level directory e The pipeline was written by Ren Fa bender A detailed description is given in his di ploma thesis available as a PDF file together with this manual Function Call o2k pipeline image cat frames sky mode sum kappa sum cuts flags flatfiels Remark o2k pipeline is an OMEGA2000 context command which calls the routine OMEGA pipeline prg The pipeline can also be called without the context command in the following way O2K UTIL pipeline PRGs OMEGA pipeline Defaults icat automatic use image catalogue created by current observing macro session frames 3 use 3 image on either side of a masterframe for the sky determi nation 1 e determine sky from a total of 7 images mode 2 5 outlier clipping mode with x lt
116. nsist of 20 dif ferent positions with typical relative offsets of 20 30 arcsecs After 20 1mages the telescope 1s moved back to the origin and this origin is then shifted according to the repetition pattern Figure 42 before the basic pattern 1s started again This way 400 different positions are de fined Figure 43 after which the pattern starts back at position 1 This also holds 1f the dither pattern 1s specified by a user supplied file Note The positions of the primary dither pattern are all within a square of 18 arcsecs from the origin the shifted origins for the repetition pattern are within a square 5 5 arcsecs from the origin Thus the maximal waste area at the edges where not all images overlap 1s 23 5 arcsecs on each side The effective central observing area where all images overlap is a minimum of 14 5x14 5 arcminutes for any number of dither positions used Please note that the waste area 1s not really lost If the same dither pattern 1s used for all pointings one may regard the whole mosaic as subjected to this dither pattern This however complicates data reduction considerably AY AX Figure 41 Standard dither pattern with 20 positions for integer pixel offset red and fractional pixel offsets blue repetition offsets AX Figure 42 Offsets for the repetition patter OMEGA2000 manual doc Figure 43 Telescope positions for a complete cycle of 4
117. ode should be set to minimum This ensures that the back ground is taken mainly from the sky exposures and will not be influenced too much by the extended object The angular distance of each exposure relative to the first one in the cata logue is limited to typical dither offsets So the sky exposures are ignored in the summed im age OMEGA2000 manual doc Appendix 1 Filters Broad band filters Filter cut on 5 cut on 50 cut off 50 cut off 5 comment block z 081 083 098 099 SDSS ISSAC Y 097 0996 1 069 1 099 MANOS J 10 110 1345 1355 Jo 14146 1156 1250 1259 MANOS m 1243 1254 1359 1369 MANOS 145 1165 1325 1335 NIRIJ 1485 151 1785 L810 2MASS K L86 194 228 234 197 200 230 233 2MASS 197 200 240 242 EE offi 1 52 153 162 163 Tdwafs Methane on 1 63 164 175 176 Tdwafs Table 4 Broad band filters x Filter x comments block Narrow band filters 1 Pay 1 094 Important e He Due to the extended detector sensi Fell 1257 tivity beyond 2 6u several filters Pa p 1 282 Mah But iy a dd hs R 2 a cking filter These are marked by an arias AV ee asterisk in the last column Filter He I 2 058 maa awm La ul I a cally Inserts the appropriate block oe SAR ing filter and correct
118. of which the spooler knows which fits keywords to list OMEGA2000 manual doc Besides that the program also lists the number of records in each file and ist size in bytes SDATSPOOLER config KEYS LIST is used if the user does not supply a keyword file FitsList device nfiles firstfile device name of the tape drive e g dev rmt 0cn nfiles number of files to list firstfile first file on tape with which to start listing spooler control Oueuecontrol reset Deletes all entries 1n the queue QueueCcontrol LEST Lists all files in the queue Q e eControLl restart Restart the spooler If there are files in the queues not yet copied to tape these will be now copied QueueControl stop Interrupt copying to tape Resume with restart Environments DATSPOOLER DIR datspooler cshrc It is necessary to call this file once at the beginning by source datspooler cshrc How ever in most instancies this 1s done by the instrument control software Files used by the spooler DATSPOOLER DIR common spool dat spool DATSPOOLER DIR common spool dat tmp Holds the name of the files to be saved following the call QueueFiles path file After that thsi file is copied to dat tmp Programs All programs are located in DATSPOOLER DIR bin Those starting with DAT are called from other routines but may also be used directly DATeod dev Writes an EOD end of data mark to tape If done at the begin ning of the tape this deletes the tape reset tape
119. ommunication to the telescope syntax chopper angle degrees Defines the chopping angle Ihis command just changes the FITS header no communication to the telescope syntax chopper mode rectangle sawtooth dc Defines the chopper mode Ihis command just changes the FITS header no communication to the telescope clobber type USER syntax clobber yes no on off Enables disables overwriting existing files Default is no coadds type USER syntax coadds t or subreps skips Sets of coadds Bor Madri F GE Coadds 4 F of Skips as identical with of subrep sub repeats done by ROE At saving time coadds are coadded to a Single crep image ODE TOP skips defines the first fskips of subreps to be thrown away Option t is used without other arguments and just checks the last coada and itame command if the values has to be adjusted according to possible combinations of coadds and minimal sub integration If there are adjustment found a warning is given Without option the current state is shown coadds 1 sub skip 6 wanted coadds 9 which informs that the last subrep count set was 9 but the last efficient integration time to use were to small and only single coadd read instead of 3 reads fits additional to the 6 skipped into that efficient integration time Attention For Midi the itime as effective itime of a coadded image is hold constant when coadds command or itype command is used
120. on 75 13 12 List PTT Ses OR AISE an ee 75 L5 IS ESCEMSEMIESOMIADO o nee 75 4 Onlinexsortared ctuonpiOipelin uyum ya u ua uqu R 77 JI T T One MO essen ee 82 142 Blowcharts TOF Pipe Idee terete doka bansa een 85 E OVVIE op RE RM 85 14 2 2 0Kky De tern iDa ans 86 14 2 5 u mm madoneot duleted map 87 4 5 Examples or pipeline Tesults ease ibm ee 88 14 3 1 Images taken with O2K JICKEB anne one re do 88 14 3 2 Habes taken with 02K Sky O POT U an ee EM E 89 Appendix FE S a di A Be Ri 90 Appendix 2 Flat Held exposure times ao heh ER eet tar a EUER FOU 92 Appendix gt Detector POP LIOS a nk 94 Appendix 4 DAT spooler anne GEJ W 95 Appendix 5 FITS keywords written by OMEGA2000 98 Appendix 6 Complete list of Th3CrOS 5 oe a oa ta coda odi rca on dice vm ve ds CEDE Ed OE 101 Appendix 7 Recommended focus ftelds a 126 Appendix 8 AstromelricTieldauuuu na Saa i devi tva i Eres oe o ba A 134 Appendix 9 Photometric Zero DOT ui 144 Appendix 10 Photometric standard Stars cccccccccccccsssssseeeccceeeceeeeeeccceeeesauaeseeeeceseeesuaneeees 145 Appendix 14 LINUX PC as X Termial so e esse la 146 Appendix 12 Basic MIDAS commands 147 Appendix O HOS SEV cuoi ee oh tid W d ver
121. ordinates on the detector using a constant pixel scale OMEGA2000 manual doc enable extraction of the pure source signal But the situation is different as we automatically get neighbouring sky for free in our images Only in case of very extended objects filling a good fraction of the FOV do we still need to take separate sky expo sures The technique to determine the sky from the science frames themselves is called dithering Between science exposures of the same field the telescope is offset by small amounts bringing the objects to slightly different places on the detector This allows a 1424344 142 given pixel to see pure sky n most of the images In the example at right pixel A sees pure sky in frames 1 to 4 pixel B only in Figure 13 Determination of frames 1 and 2 Stacking images via a median like process elimi n un nates object signals and cosmic ray events The result is a frame with pure sky only There are two caveats however As men tioned above offsetting the telescope introduces a field rotation Thus in dithered images the images cannot be aligned perfectly The effect for low declination and small dithering offsets is small however Furthermore the sky illumination 1s changing both in level and in shape FaBbender 2003 Therefore a consistent sky image can only be extracted from the science frames taken shortly before and after a given image From these the contemporary sky frame is extracted by a
122. ot_single single Integration times in seconds tot pointing 1s the total integration time for the pointing This parameter determines the final limiting magnitude of the pointing Tot_pointing tot_single images are take at different dither positions tot_single is the time for one integrated image which is equivalent to the integration time at a one dither position Tot_single single exposures are added up in memory be fore the final single image with an integration time of tot_single seconds is saved on disk Single is the a single exposure integration time This parameter is to be optimized for each filter to allow background limited observations while being within the linear de tector regime Note To prevent truncation errors when calculating the number of repetitions tot_pointing should be a multiple of tot_single and tot_single should be a multiple of single object_identifier Character string for the IDENT descriptor If blanks are contained the string should 99 be enclosed in Stare pos tel pos Starting position of the dither sequence This parameter allows the continuation of the dither pattern at a specified position after an interruption As a default the telescope is expected to be in the start_pos 1 position tel_pos PREV from where the dither pattern s continued with the next position If the current telescope position is the field acquisition position tel_pos AO then the telescope if offs
123. ough n2 Default is all i save the integral of the selected frames 1 write all images into one FITS file FITS cube t save all images as FITS bin table file Jaffe Cotton b split the data into fitstable batches and write to dest g split the data into single DCR images and write to dest d do not create FITS files Just dump the shared memory framebuffer c overwrite existing files for this save operation only p save not the actual sequence but the previous one S speed up version of autosave by immediate direct buffer saving while reading the buffer in contrast to normal autosave without the s option which is saving the data after buffer is filled Currently only supported for MIDI batches and tables If used in a single save command it takes the current read buffer for parallel saving OMEGA2000 manual doc Attention Option p is only thought for interactive usage It is not a good idea to use it in a macro If no filename is given the default filename is used With optici B the filename nicht be a device Jdev podl Example Save p el Speedy tad p EL which saves the previous sequence as cube fits previous sequence as integrated single fits image actual sequence as cube fits and actual sequence as integrated images After a save the filesystem will be frequently checked If the capacity is below a certain value you will get a warning from the system Examples save b
124. ow three pull down menus provide further options 5 omega z000 Co ega 2000 Contro Op Modules v option Controls 35 7 options Sound SavePath HacroPath 0 ObjectPath 2 Init Hheels Display ji Re init ROElec Telescope system 5etup Sat Check StripChart Logfile Quit System Kill Shell sy oSA S Omega2000 Controls 4355 BAFFLE SHIELD HO OUT D FILTER HB1710 c Hheel Hacro HB1710 o cyetIs Reads ieff 26 3h 3 0 Resets 1 sefi 26 3 Filename Figure 36 The camera control window with its drop down menus The drop down menus provide the following options File Menu Init wheels sends all of the filter wheels back to their zero positions Re init ROE resets the read out electronics System setup will bring up the initialization window Help Close controls Quit system will quit the GUI Modules Menu The modules menu starts the different modules each of which has its own description section Display should start automatically Telescope Telescope control should start automatically Satcheck Turns on audible saturation warning Stripchart Keeps a visual record of the past several images Temp Pressure Displays a graph with the pressure and various temperatures inside the dewar Figure 37 Monitoring temperatures and pressure of the dewar Options Menu e Sound calls up a sound menu where a specific sound
125. own s status offline online em Motors orftline camerbra dgrrect t temperature controller offline camera direct syntax init telescope name f number s status Initialize the telescope Valid telescope names and focal ratios are defined in CAMHOME src camera h telescope lab ca35 ca22 cal2 hd07 ukirt f L9cCal 73210 13 8510723 23 43 s status foffline EPICS serial syntax init wheels Read filter aperture wheel database and move wheels to the ZERO position detent position iniwindow type USER syntax iniwin Opens a window to setup the camera telescope configuration If you leave the window using the OK button the camera the telescope and the wheels will be initialized if their setup was changed all forces a complete re initialization whether or not anything was changed interactive Lype Syntax OMEGA2000_manual doc ENG interactive on off yes no If you use the interactive mode the outputs are blocked after 19 lines until you enter RETURN Default is yes All shell outputs are blocking if you use interactive ves and you may lose messages if you set interactive no instrangle EVPpE Syntax itime type syntax kill Lype syntax USER instrangle angle Sets angle as the instrument angle for the NSEW orientation For relativ telescope movements the complete correction angle is currently given fratio e g ALFA F25 22 0 ang
126. path if not local of image catalogue containing all images to be reduced If 1cat automatic the online reduction 1s activated 1 e the image catalogue created by the currently running observing macro is used and the data 1s reduced in real time LABEL icatalog Sky frames Number of frames on either side of a master frame for the sky determination Thus the total number of frames used for the sky is 2 sky frames 1 LABEL frames P gt P4 PS PG sky mode mode specifier Mode for the sky determination 3 different sky modes are available minimum mode fast median mode and the outlier clipping mode The modes can be specified via an integer flag or via a string identifier The minimum and outlier mode have a second specifier 1 Minimum mode mode 0 n or mode min n n is an integer specifying how many of the smallest values are averaged n 1 is the real minimum n 2 takes the average of the 2 smallest values and so on 2 Median mode mode l or mode med Takes the median of each pixel col umn 3 Outlier clipping mode mode 2 k or mode out k k a real number speci fiying the clipping threshold as k sigma above the median All outliers are clipped off before the median of the remaining values 1s taken LABEL mode sum parameters n average action flag sum save flag Parameters for the summation of single Images n average integer specifying from how many images the reference sum frame 1s calc
127. r i is U TENE E E gl a i wat h i p I OE dr eC A NE DARIN QE d oUm u zi 1 i a a a at a LJ m a i E E U a Ec m a a BC L ELI amp od T m k U i i E 1 a f m r F le Ri L m a T s il 7 u ad PL if i T z A E a 5 Erg m R J LU a b a Eu m ET mr z i n X x m Wu a a u L uL li F i 1 ou a u a ir L 1 y p a T U R Nr w ce iun Z RC E m E 3 ph z g p mis sj ai a i uw XL a Ls z w T E B 1 E a z u I P Tm u m im k T P A HT a ja ae 2 ku 1 Figure 63 Astrometry field at RA 18h finding chart for astrometric stars from M2000 Astrometry 22h 13 43 13 38 13 33 O LLI Q 13 28 13 23 13 18 22 345 22 340 22 335 22 330 RA h s T a L m L F a k i a 5 5 a T F m i B x oir N E UB u A a F z EE i E i n t E pik Ei a i t 1 a m r a t F u i u 1 l i S A 5 n m g F sa i LI a u E Hou I M nih r E E ii a m E 1 uA i k a a s 3 u a F z zu r i a Ua T E E T z Figure 64 Astrometry field at RA 22h finding
128. r FPA 437 right The read out noise for a double correlated read i e two reads for a single image is 17e The detector is clocked with a rate of 320 kHz resulting in a minimum integration time of 2048 x 2048 pixels 2 images 32 channels 320 kHz 0 80 sec The conversion factor from counts to electrons EPC electrons per count has been deter mined for all 32 channels separately The values are almost constant at an average of 4 5 A detailed list is given in Table 3 channel 1 2 3 4 5 6 7 8 9 10 1112 mn is 16 ec sec i111 li Table 3 Conversion factor electrons per count EPC for each of the 32 channels The channel layout is show in Figure 16 Channels are numbered along the fast direction starting with quadrant I This numbering scheme has been adopted in Table 3 4 2 pa tw ro Pal abal I ihabetabebiis Lala Jaa dal al al Ls IB LILITZSRE gs DALAI SNES NE Figure 16 Quadrant and channel layout for the HAWAII 2 detector 7 1 1 Read out modi implemented for OMEGA2000 This description of the read out modi is taken from the PhD thesis of Zoltan Kov cs 2005 There are three output modes available for the chip which can be controlled via the readout patterns In the Single Output Mode all data 1s routed through only one channel per quadrant If the chip is set to Eight Output Unshuffle Mode the data 1s spread across all the output chan
129. r left out of macros For example quit will exit a macro at the point it occurs no further instructions in the macro will be executed Also if interactive is on and Is dir or history are used in a macro the macro could stop executing and wait for a carriage return Double buffering It takes a considerable amount of time to transfer the data from the camera and save it to the hard drive on the workstation To reclaim some of this otherwise lost time Omega prime has been configured with two image buffers Thus a new image can be read out while the previ ous image is being saved To implement this feature the macros should be written as in the example above with a sync tele after the telescope offset and save commands The GUI will then only wait until the telescope move 1s completed before starting the next read the save command may still be in progress When observing in the K band the increase in efficiency of observing the fraction of time spent actually integrating on source is significant With 3 second integrations 11 repeats and saving images 2 through 11 as an integrated image effi ciency jumps from 33 to 40 Using macro commands in a shell script or MIDAS prg All of the above macro commands can be used in shell scripts by preceding them with the string cmd 02000 Example for the use of macro commands a MIDAS procedure set format I1 F6 1 set image parameters emo 02000 Grep qTorep Semd 02000 itime itime S
130. r the seeing was good enough to bother saving the data just leave this on last BAD Toggles between displaying the bad pixels in red or not Note that the bad pixels are ignored when determining display cuts only if the bad pixels are turned on The bad pixel mask is stored in path Cuts Display stretch control This button brings up a menu with various options for de termining the minimum and maximum display levels The options include e Cuts Allows you to enter your own minimum and maximum display levels in the Min Cut and Max Cut windows e 67 Sets the display range to cover 67 of the full dynamic range of the data e 90 Sets the display range to cover 90 of the full dynamic range of the data Min Cut Max Cut These windows show the current minimum and Single Sum Ave single will display each individual read as it comes Tele Movie Image Sky Send OMEGA2000 manual doc med3 Sets the display from mean 3sigma to mean 3sigma meds Sets the display from mean 5sigma to mean 5sigma 3 10 Sets the display from mean 3sigma to mean 10sigma minmax Sets the display range to cover the full dynamic range of the data maximum levels used for the display They will 5 BAD au automatically update each time a new image is dis played except if using the Cuts op tion medj o off the camera Sum will display the sum of all im a ages taken in the current series Average displays the ave
131. rage of all images taken in the current series Provides for offsetting the telescope directly from the image dis play which is useful for centring standard stars or science objects Click on the tele button to get a green circle Place this circle on some object on the display and click there Calculating centroid Move the cross which appears to where you want this object to be moved Plays a movie of the series of exposures currently in memory shows which image 1n a series of repeated exposures that is currently being displayed The sky button small square tells the computer to subtract a sky frame from the images before displaying and is on when the square appears green The file used for the sky frame is specified by name in the window to the left of the button This sky subtraction also effects the pixel values displayed in the upper part of the window Be aware of this when checking count levels saturation of a displayed image Send the current image to the data base of the strip chart Ave 9 3 3 Telescope control window Telescope Controls W355 svob xO4 CA3 5m 2 35 0 45 pix AH 1 075 UT 02 37 54 ST 2 06 19 R A 2 37 48 5 Equinox Decl 16 49 34 3 Mod main S dx S dy set zero Zero Hame Hame Aligha Della Emx Smig Coment I Delta Eqnx Vmag Comment Object List dx 14 2 dy 31 5 TH 33 x Figure 40 Telescope control window Basic control of the telescope such as
132. ral type and visual magnitude appearing at the bottom of the window The coordinates can be sent to the telescope computer with the Move button A log of all previous exposures is kept displayed as green squares on the SAO map This feature 1s useful for following the progress of observing macros Clear Frames will clear the display of the old frames though future frames will continue to be displayed OMEGA2000 manual doc The SAOmap can be turned off by reselecting the SAO map option in the file menu of the telescope control panel Using the quit option in the xwindows menu will also kill the tele scope control panel 9 3 5 Air Mass Window The airmass window graphically displays the airmass of the currently selected object red dot as well as a trac ing of the airmass over several hours of time blue line The number of hours depends of the width of the win dow This feature is particularly useful when used in conjunction with object files Objects selected and set from an object file will show their current airmass in the airmass window The airmass plot will automati cally reset to the current telescope position whenever the GUI queries the telescope computer for the current position for example when a read command is fin ished The airmass window can be turned off by reselecting the Airmass option in the file menu of the telescope control panel Using the quit option in the xwindows menu will also kill the teles
133. red level Detailed behaviour depends on the time of the day Evening If the exposure level in the test exposure is above the specified saturation level no images are taken The procedure 1s aborted if the level is above the monitoring level as the sky 1s still too bright If it is between the saturation level and the monitoring level it loops back and takes another test exposure This is done until the level is below the saturation level Then images are taken with an exposure time scaled on the basis of the last test exposure to reach the desired level If the resulting exposure time turns out to be longer than 60sec the user 1s prompted for confirmation before the exposures are started Morning If the exposure level is above saturation the procedure is aborted If the resulting exposure time is longer than 60 sec the user is prompted for an exposure time when taking of images should be started Level monitoring is then continued until this limit is reached Then the images are taken Should the level reach the saturation limit in the shortest integration time available the procedure is terminated If check option is used a test exposure is taken after each read cycle and the exposure time is adjusted accordingly This 1s the default 13 4 Focus test For the focus tests we strongly recommend to use the focus fields provided in Appendix 7 on page 126 These have been tested and work fine in most cases Problems were encountered for extr
134. rmal infrared and approximated as a 273 K blackbody with e 0 02 Emission from the Earth s atmosphere at 1 5 25 um is shown Zodiacal scattered light at the ecliptic pole approximated as a 5 800 K blackbody with e 3 x 10 14 Zodiacal emission from interplanetary dust at the ecliptic pole approximated as a 275 K blackbody with e 7 1 x 10 8 Based on observations from the Infrared Astronomical Satellite IRAS Galactic background emission from interstellar dust in the plane of the Galaxy In the plane of the Gal axy away from the Galactic Centre it can be approximated by a 17 K blackbody and e 10 3 OMEGA2000 manual doc SEP South ecliptic pole emission as measured by the Cosmic Background Explorer COBE spacecraft CST Cryogenic space telescope cooled to 10 K with e 0 05 CBR Cosmic background radiation 2 73 K blackbody with e 1 0 The dominant source of sky background emission in the wavelength range concerned by OMEGA2000 1s the OH emission often expressed in units of Rayleighs 1 Rayleigh unit 10 4z photons s m sr 1 5808x10 7 A W m sr 1 Rayleigh A 0 1870423 phot m s nm r A detailed calibrated OH emission spectrum is published by Maihara 1993 Ramsay 1992 a high resolution spectrum by Rousselot 2000 For a complete overview of the nightsky background see Leinert 1998 In narrow band imaging the level of the night sky does depend critically on the exact pass band Therefore no e
135. rresponding xxx type parameters center x center y size engineering modes of Omega2000 SBE single pixel read stays on the pixel and clocks as often as the field size of the channel parameters x pos y pos l reset level read holds the reset level and reads the array ENG delay Set delay between two cycles Unit milliseconds MPIA electronics only USER dir filenames Executes ls l in current directory The output stops after l page to proceed with the next page enter RETURN to abort the output enter q lt RETURN gt USER display c 1 table i x xserver f font p cU W OT Colors 14 220 defaulteliD0 l color lookup table gray temp heat default gray i image size 256 512 1024 default 256 for MagictMax 512 for Omega x where to open the window e g xt28 0 f font ramLky 9 0 lucrda p without argument only tries to get private colormap engstatus type ENG syntax engstatus Requests the engineering status from the camera and prints it on the screen After a Re Send Params in the Control Window the returned values of engstatus should be like this Omega MPIA ctype 2 time 0 x 10ms crep l delay rt rpc e omega 23 01 1997 17 01 Max Omega IRL not available engwindow type Syntax exit ype Syntax filter type syntax fits type syntax ENG engwin Opens engineering info window ENG exi
136. ry after step 1 while the pipeline is still working with the opened frame The output data frame s only save to use after the frame has been closed in step 3 If the data frame were opened and used by another application between step 1 and 3 serious software trouble would occur Most likely the pipeline and the other MIDAS session trying to open the unclosed frame would crash Thus a few precautions should be met to be on the save and prevent a session crash e The screen output contains the information on what frames have been closed These images are save to access with other applications e The intermediate summation results are saved on disk after every n th frame Before a new output frame is created the old one is closed Thus the summation frame with the currently highest index index sum icat fits 1s critical and should not be opened However the summation frame with an index 1 lower than the highest can be accessed and opened by other applications without any problems Predefined Modes The following examples state recommended parameter sets for different pipeline applications a Online reduction for normal observations o2k online without any parameters Uses fast median mode with a total 1f 5 frames for the sky determina tion The intermediate summation result 1s written to disk every ris frame b d OMEGA2000 manual doc Online reduction for observations of extended objects o2k pipeline icat automatic frames
137. ry out specific normally reoccurring tasks Please note that the macro utility 1s sequentially oriented e you have to specify a macro command for every action you normally would take at the camera GUI It does not provide conditional and loop capabilities However every macro command may be issued with the prefix cmd 02000 from a shell e g a MIDAS procedure the utilities presented in Section 12 make heavy use of this feature The following example shows a simple macro that moves a star to five positions on the detec tor starts a read at each and saves the data Example read Start the lst read sync wait until all previous commands are finished tele rel 25 25 move the telescope c ee E save the data as integrated starting from the second frame sync tele wait until only telescope move is finished save will con tinue read start the 2d read sync wait until all previous commands are finished tele rel 50 0 save ex f 2 sync tele read sync tele rel 0 50 Save i Sf 2 sync tele read sync tele rel 50 0 save wq SE 2 sync tele read Sync tele rel 25 25 save qeu sync tele All macro files must have the extension mac and are started from the camera control win dow lower part see Figure 36 Macro Commands In a complete list of macro commands is given These commands and syntax can be used in macros or typed directly into the command window Use with caution some commands are bette
138. s also the focus Bry 2 166 ss shift Hy 2248 continuum 2 260 Y CO 2295 supergiants Table 5 Narrow band filters All wavelength specifications are in micron Js H K Ks K Methan off 1 000 1 200 1 400 1 600 1 800 2 000 2 200 2 400 Methan on wavelength nm transmission Figure 47 Transmission curves for brad band filters He Pay continuum 1 Ol Fell Pa Fell continuum 2 transmission 96 continuum 3 Bry H continuum 4 co 1 000 1 200 1 400 1 600 1 800 2 000 2 200 2 400 wavelength nm Figure 48 Transmission curves for narrow band filters OMEGA2000 manual doc Appendix 2 Flat field exposure times Dome flats The exposure times are for a count level of 15 000 cts pixel Filter Acentre u lamp Mirror cover At sec remark KKM KM KOK KA EM we O waes Minen Fel L644 continuum 1710 Hel 2058 Hm 2122 continuum 2444 fo Tr EN 225 d Table 6 Exposure times for dome flats Twilight flats It is assumed that the telescope is pointing a direction away from the sun and that the sky is clear no clouds Filter Acentre u x powy mz N 4 sec remark o Y Kema NEN SZM KEN d p do EEEE s TT we 1 I BENE NN RN E m Hm 2 continuum 2260 EE l 295 fT Table
139. s rotator table GUI x display name m mute mode do no talk to device for tests only rtime type ENG syntax rtime Set reset time of clock tics at the beginning of each cycle line MPIA electronics only saad Eype ENG syntax sadd x sr a Do shift amp add on images 2 through n Find peak pixel around xw m a box ot Size Ttdi Overwrite image l with the result of the shift amp add procedure satcheck type USER syntax Satcheck on LIMIE Switches the saturation check on The optional limit uses absolute counts of the A D converter These counts range from about 0009 55000 The mo slineertity Starts at about 20 000 counts which s the default Timer Ti sound xs ons you get a accoustic warning syntax satcheck off Switches the saturation check off This is recomended at intgration times smaller than about 150 ms Magic Cameras save type USER syntax save pee PEST sa Fi Fern eae 2 exp ES E Le or lt 9 e lfilename devname se Save frames in the shared memory according to the actual cycle type ctype ATTENTION All files starting with the prohibits the automatic storage on tape with the datspooler tool at CalarAlto A comma delimits multiple saving sets done from the same data might be sequential or parallel executed from software f save from frame n first frame is l save upto frame n last frame is r save only frames from nl thr
140. s written into the fits header under the keyword OBJECT for the current image It will be updated automatically 1f object selection is done through ob ject files recommended or can be changed by hand Sky Clicking on the sky button writes a sky flag into the fits header but otherwise has no effect Comment to be included in the FITS header Macro Here you specify a macro to be read into the macro buffer The filename without the mac extension 1s all that 1s necessary all macros must have the mac extension The macro file must be in the MACROS directory specified under the macro path in the options menu see above Please refer to Section 10 on page 46 for the macro syntax and commands Execute Pause and Abort control the execution of observing macros reads and running MIDAS prgs Note that 1f a pause or abort is issued the macro will continue executing until the current command is completed Check in the command window to be sure that the pause is in effect Clicking on continue will continue executing the macro after the pause This 1s useful when changing the dome slit segments In the case of a MIDAS prg running the abort will take effect only after the next major loop e g the next focus setting in a focus test or the next dither position in case of an observing sequence Disk The green portion of the bar indicates the fraction of the selected disk which is still available If you are taking lots of data keep an eye on
141. series of frames with increasing expo sure time the bad pixel mask from flat fields the dark images with the blank inserted Fitting the signal for every pixel as a function of exposure time with a straight line isolates well be haved pixels in the flatfield series those following a straight line from the bad ones by ana lysing a histogram of the slope values found For the dark series the slope gives the dark sig nal per second This analysis takes the following steps further documentation see header of prg file e Take the series either dark or flat e Create an image catalogue o forexample create icat raw XXX fits e bias extrapolation root frame_list o for example bias extr test raw 1 4 8 12 e Analyse the output frames root _CONSE DGE o root slope bdf O XOOE EIS DGOL 13 11 Monitoring atmospheric transmission o2k transmon magnitude filter By comparing the observed counts from a star of known brightness e g from the 2MASS catalogue with the theoretically expected counts one can get a feeling for the amount of at mospheric absorption or at least about variations of it The acquisition frame 1s most conven iently used for this purpose as usually the brightness of the alignment star 1s known The procedure uses a simple approach in that the user places the cursor box around the object of her his choice and second into the local background The observed count rate 1s calculated from the difference of the two backgro
142. sky exposure ET PZ P gt P4 E 1catalog Name of image catalogue that contains a list of all taken images The name of the im age catalogue is automatically passed on to the pipeline and can be used for online data reduction If no online or further pipeline reduction is desired this parameter 1s just a dummy For online reductions the icatalog parameter should by specified with distinct names to prevent pipeline reduction of the wrong data set itine IDEOt cDOSDESng4Lot ssngle BinglaA Pot single sky Integration times in seconds tot pointing 1s the total integration time for the pointing This parameter determines the final limiting magnitude of the pointing Tot_pointing tot_single images are take at different dither positions tot_single is the time for one integrated image which 1s equivalent to the integration time at a one dither position Tot_single single exposures are added up in memory be fore the final single image with an integration time of tot_single seconds is saved on disk single 1s the a single exposure integration time This parameter is to be optimized for each filter to allow background limited observations while being within the linear de tector regime tot single sky 1s the total integration time for a single integrated sky exposure If this parameter is omitted the object integration times will also be used for the sky The to tal integration time for sky observations 1s the fraction tot single
143. speaker v volume 1 100 Without parameters sound prints the sound status status types USER syntax status Returns the comlete status list depending from the SW mode SINGLE MAIN INTERFACE stripchart eype USER syntax stripc x xserver Opens the strip chart window x where to open the windwp e g xt28 0 subwin type USER syntax subwin HW SW auto wid xlstart ylstart xsize ysize subwin on off HW SW auto wid subwin clear HW SW auto subwin HW SW DET currently only implemented for instruments with MPIA ROE2 Enables disables clears and sets the hardware HW and or software SW subwindowing Instead of HW SW there is also the auto option where the SW will assume that the given windows has to be acquired via optimal HW windowing So the software will automatically convert auto given windows to SW and HW windows subwin on auto will clear all HW windows and redefine the needed HW windows for the instrument via current SW windows list If the instrument has no HW windowing available enabled always fullframe readout with SW windowing is executed Subwindows are only added if the list of subwindows is not yet full and wid number is not yet used for a subwindow where fwid of SW windows are overwriting any wid of HW window OMEGA2000 manual doc definition But for HW windowing only the wid of the HW window definition is used Currently max subwindows count is at lea
144. st 2 times number of data output channels of the detector NO But for ROE2 the max of HW windows is given by the roe variable xxx list xlstart and ylstart values has to be 1 size Examples aclival lon control subwin off Any windowing is switched off only full frame Subwin on HW and SW windowing with current subwin information will be used subwin on SW SW windowing will be used subwin off HW HW windowing will not be used subwin off HW 1 Dectivate HW window id hwid 1 subwin on SW 2 Activate an deactive SW window swid 2 window structure setting subwin SW 12 1 1 100 100 SW window with wid 12 of size 100 100 from left lower edge 1 1 is appended to the list of SW windows according to unique fwid 12 and window definition free space subwin HW 12 1 1 320 10 HW window with wid 12 window structure clearing subwin clear HW Clear all HW windowing definitions subwin clear SW Clear all SW windowing definitions subwin clear Clear all windowing definitions ATTENTION Setting of windows coord does not include activation of any windowing PS Some instrument implementation might apply only squared HW subwindows taken xsize 2 Other instruments might support only a single HW or even SW window until now MIDI for example implements only HW windowing EM V JitFeCEiOlM_ Without or with HW or SW or DET as parameters subwin prints the current settings of HW or SW or DET sync type USER syntax sync read
145. standards e g from Elias et al 1982 AJ 87 1029 are too bright for this camera Finally enough copies of my loose leaf stack of finding charts had been requested that it seemed reasonable to produce a more formal compilation thus this work The standards for which these finding charts are provided come from the UKIRT Faint Infrared Standards list of Casali 1992 JCMT UKIRT Newsletter 4 33 and this is the source for most of the data which appears in the following table The only new material here are the finding charts themselves and perhaps the packaging The finding charts on the following pages were obtained through K filters with the MAGIC and infrared cameras at the Calar Alto 2 2m and 3 5m telescopes over the course of two years of observing In several cases identification of the field from Palomar Observatory Sky Survey POSS images was not so straightforward the intrinsic colors of the stars can significantly alter the relative brightness of the different stars in any given field of view In addition proper motions can change the relative positions over the 50 years since the first POSS was produced It is hoped that these finding charts will thus be useful to the infrared observers David Thompson 19 February 1997 Cover This image of FS16 and FS17 shows the field of view of the Q camera on the Calar Alto 3 5m telescope 6 8 arcminutes square produced from five offset 5 second images Nun Other _
146. stro 18h 20 e xe e 10 0 19 00 20 00 21 00 22 00 23 00 0 00 1 00 2 00 3 00 4 00 5 00 UT o moon Figure 66 Elevation plots for the astrometry fields July and October OMEGA2000 manual doc Appendix 9 Photometric zero points Expected count rates for a star of Omag with flat spectrum in f preliminary to be verified filter photons cm s counts sec J 2 37E 05 4 78E 09 H 1 10E 05 2 22E 09 Kp 8 25E 04 1 67E 09 K 9 32E 04 1 88E 09 Table 8 Photometric zero points counts for zero magnitude Appendix 10 Photometric standard stars The list of UKIRT faint standard stars as prepared by Dave Thompson is appended at the end of this manual We plan to update the fainting charts as soon as possible For the astrometry fields page 134 and focus fields page 126 we plan to give J H Ks magnitudes from 2MASS for some representative objects Otherwise the 2MASS web page provides more data under http www ipac caltech edu 2mass releases allsky 1index html OMEGA2000 manual doc Appendix 11 LINUX PC as X Terminal OMEGA2000 is operated most conveniently from a dual screen X terminal For this purpose we use a LINUX PC emulating an X terminal This way we ensure that we almost always do not run out of colours despite the use of MIDAS display netscape and acrobat etc To launch the terminal one has to log into the PC with the name o2klinux as follows User o2k Password ask staff same as on fire35
147. t Shut down of the camera software Within a macro it will just terminate macro execution see quit USER filter position Where position is a filter macro defined in HOME info fmacros x Ihese macros define the position of all wheels following means use the default position availabel for lyot stop only means leave this wheel as it is Without parameter filter shows all available filter macros and the actual one filter is a background process and should have a sync after it when used in a macro USER EIES Prints the actual FITS header The output stops after 1 page to proceed with the next page enter lt RETURN gt to abort the output enter q lt RETURN gt syntax get type Syntax gui type syntax help EVDE Syntax Syntax syntax history type Syntax syntax syntax hpmove type Syntax OMEGA2000_manual doc fits comment text Sets text in the FITS header as COMMENT ENG get Offset l izd Prints shared menor page entry offset i integer entry default f P loat entry d double entry Sw SEFLNGNEEY USER gui x xserver f font starts a graphical user interface GUI for the camera For the description of the otions see help control USER help prints the list of commands help command prints information about the specified command syntax descirebes the various parameters and switches type USER nor
148. t M et al 2001 M2000 An astrometric catalog 1n the Bordeaux Carte du Ciel zone 11 lt lt 18 Astronomy and Astrophysics 376 325 332 Rousselot P et al 2000 Night sky spectral atlas of OH emission lines in the near infrared Astronomy and Astrophysics 354 1134 1150 16 Subject index 2MASS catalogue 20 astrometry calibration 20 fields 135 atmosphere important absorber 9 transmission 76 windows 8 background emission sources 9 limited regime 15 subtraction 16 thermal emission 8 bad pixel mask 75 baffles 27 calibration 75 calibration file 82 dark measurement 52 flatfield measurement 52 photometric zero points 145 standard stars 146 camera 21 control 35 catalogue objects 46 CCD 11 centre to corner distortion 16 channel layout 22 clocking rate 21 control electronics 30 conversion factor 22 electrons to counts 22 dark current 19 detector 95 bad pixel mask 19 linearity 19 over exposure 95 reset 11 saturation 11 dewar 28 ditherng 17 67 extended objects 70 pattern 67 double buffering 48 field rotation 16 file listing disk 76 tape 76 filters 27 91 FITS keywords 99 flat field 18 dome 19 54 exposure times 93 sky 19 focal plane array 11 focus 18 58 fields 127 position 31 GEIRS 33 graphical user interface 32 HgCdTe 11 integration time calculation 15 Login 32 macros 47 102 MIDAS session 44 mosaicing l6 night sky level of 10 object catalogues 4
149. t HAWAII 2 detectors giving an unprecedented field of view for IR cameras of 15 4 on the sky As such its prime application will be survey work Due to the nature of astronomical objects this will be targeted towards the dusty the cold and the distant universe One should keep the survey application in mind when using OMEGA2000 because e g the observing utilities provided were written with primarily this sort of observations in mind 2 2 The infra red sky Beyond the optical window the atmosphere becomes increasingly opaque and ground based observations are only possible in certain atmospheric windows These are in the Johnson system called J H and K for wavelengths up to 2 5 um see Figure 1 The major atmos pheric absorbers and central wavelengths of absorption bands are H2O 0 94 1 13 1 37 1 87 2 7 3 2 6 3 A gt 16 um CO 2 0 4 3 15 um N20 4 5 17 um CH4 3 3 7 7 um Os 9 6 um Cox 2000 The depth of the absorption troughs does depend on the water vapour con tent of the atmosphere Aimosphenc transmission Wavelength um Figure 1 Atmospheric transmission as a function of wavelength in the infrared wavelength range Cox 2000 At wavelengths longward of 2 3 um thermal emission from the atmosphere and telescope produces significant background see Figure 3 Shortward of 2 3 um the sky signal is domi nated by airglow emission from molecules primarily OH and O This background can vary significan
150. tax casspos angle cd type Sets angle as the actual cassegrain angle Just a FITS header entry Without parameter the actual cassegrain angle relative to NSEW will be printed This is actual cass angle t oassorrt This value is written into the FITS headers as CASSPOS USER syntax cd directory Changes directory for save operations UNIX style If you change the directory the new filesystem will be checked If the capacity is below a certain value you will receive a warning from the system To check the currently usde directory use the command cd to get the directory and the free capacity If a basename was given for the default filename the new directory is searched for matching filenames which could result in a conflict by a larger digit value in the name If a possible conflict was found next free larger value is taken as next default filename else the default filename Stays the same Without argument the directory is UNIX like set to the home directory of the user The directory save path and the freespace is always output chopper Eype USER OMEGA2000 manual doc It this command is available at UKIRI only syntax chopper beam A B Set chopper to position A or B swithes to DC mode The communication is done through IRL electronics syntax chopper throw arcsec Defines chopper throw peak peak in arcsec on the sky Ihis command just changes the FITS header no c
151. tegrated signal in the actual cycle This method of interlacing the neighbouring readout cycles of lines is the most effective solution for CDS because each line is reset and the bias values are read immediately after reading the integrated pixel values Figure 23 The CDS with fast reset waits until the video signals in the whole array have been read before resetting the unit cells in the next cycle To obtain just a single image the CDS with fast reset takes the same time as the line interlaced mode but for a se quence of many repeats the latter is much quicker Perhaps the technique of the line inter laced read can guarantee the most stable operation of the image sensor because each line in the frame 1s read out twice before and after the integration As it can be seen all the lines of pixels in the adjacent readout cycles are interlaced in contrast to the previous modes where each readout cycle carries out a complete readout process This readout mode is also available for scientific purpose 1 readout cycle 2 readout cycle Read Reset Read NE Read Reset Read Integration Read Reset Read ZE Read Reset Read Integration 1 line 1 line 1 line f 1024 line 1024 line 1024 line i 1 line 1 line 1 line f 1024 line 1024 line 1024 line Figure 23 The scheme of the line interlaced read row time Figure 24 Alternate representation of the line interlaced read Multiple End point Read This read
152. tele filter Savell Llnone farr macro l Waits for termination of the named process sync waits at least seconds before checking on any process to sync for to ensure startup of previous command which might need time on a busy system if none also with others is given it does not sync on processes If no process parameter is given sync waits for the termination of all background processes listed above and currently running in the system Without time specification might be given as float the sync waits at least 2 seconds This command is needed for writing macros since commands like read do not block the execution of the next command A typical sequence could look like this read read data Sync wait for all running processes tele rel 10 10 move telescope 10 north 10 east save i 2 save data sync tele wait for the telecope stops read next read If a parameter of sync is given as Macro or all and the sync is started from inside of a macro this macro or all string is just removed sync waits only as a command outside of a macro on the termination of the main macro level sync without process specifications always waits on all processes with the exception of the macro process sync all waits on all processes including the macro process sync none waits on neither process only waits for the given time or 2 seconds for default system type USER
153. th this name This file is a plain ASCII file with AX AY in arcsec per line no blanks allowed The first line is a comment and exactly 20 offsets are required The offsets are relative to the previous position The standard repetition offsets see be low are used also in this case This file has to be located in the current path The standard mode should be integer offsets because it facilitates a later summation of several images by appropriate xy shifting internal The keyword file path defined as the first keyword in the PRG contains the path information for the pipeline auxiliary files In online mode the pipeline searches this path for all relevant information Functionality The dither pattern for details see Section Survey observations 1s applied simultaneously to the object and the sky observations The sky field is specified by a distance from the object and by a direction If the direction 1s set to ALL 8 different sky positions are used the four shown below plus the 4 corner positions OMEGA2000 manual doc Extended Object Figure 44 Sky positions for observations of extended objects Comments e When the observing macro is started the telescope has to point at the object e The observing macro prepares the online pipeline data reduction The name and path of the image catalogue and the integration time are stored in auxiliary files which can be accessed by the pipeline The image catalogue 1s updated wit
154. the ouside hitting the baffle are not reflected into the dewar This baffle does not vignette the Figure 28 The two warm baffles beam e A movable warm baffle of the same principle properties as the fixed warm baffle may be deployed for K band imaging It does vignette the beam constant across the field but the loss im object signal 1s more than compensated by the reduction in thermal background With this baffle deployed no part of the warm dome is seen by the detec tor The theory behind this baffle 1s described in detail by Bailer Jones Bizenberger et al 2000 The influence of the movable baffle was tested in a cold winter night It gave the predicted gain in signal to noise Fa bender 2003 Tests in a warm summer night remain to be done Frequency Frequency 7 CG a lt f 7 A 7 SSNNNNNNNNNNNNNNNNNNNNNNNNNNS 1 1 05 1 1 1 15 1 2 Kp_SN_realratia Unitless K_SN_realratio Unitless Figure 29 Movable baffle measurement Histogram of the SNR ratios with and without the movable baffle Left panel K filter Right panel K filter 7 5 Dewar The vacuum dewar of the Omega2000 instrument has a cylindrical shape with an outer diame ter of 600 mm and a length of 1680 mm The HAWAII 2 detector and all other inner parts are cooled by liquid nitrogen to a temperature of about 77 K To reduce the heat load on these components three radiation shields are nested into each other The large dewar entrance win dow is
155. this The GUI also issues an audible warning when the disk 1s getting close to full assuming you have not turned off the sounds OMEGA2000 manual doc 9 3 2 Real time Display Pixel 1315 1685 1083 Radius min max mean dev _366 4 192 9 rmuM flx 1 8 91326 First gt paste m Max Cut mei sky ky0002__ _ Lcl Figure 39 Real time display The display tool shows one frame of the current set of data Some on line data processing techniques are available These techniques affect only the displayed data only the raw data is saved to disk In addition there are various helpful options to move the telescope to certain positions File Menu selects the basic display size e 256 changes display window to 256 screen pixels square The full Omega2000 image is displayed binned 8x8 Note that in general you will not see your objects in highly binned mode as they most often will happen to fall between the displayed pixels e 512 changes display window to 512 screen pixels square e 1024 changes display window to 1024 screen pixels square e 2048 changes display window to 2048 screen pixels square The dis play will not fit onto your monitor screen in this case e Slave Opens a second display window at a size of 1024x1024 pixel on a second screen e Quit Quits the display module It can be restarted by selecting dis play under the module menu of the camera control window Color
156. tions Menu of the camera control window You are ad vised to create a path with your name under disk X o2k DATA your name where X Is b c or d for the data disks Other locations must only be used after permission by observa tory staff The files are stored as FITS files and are not write protected It is strongly recommended to start the DAT Spooler right at the beginning of the run It automatically copies a file to tape immediately after it is written to disk see Appendix 4 on page 95 This way you need not worry about your data being safe The DAT drive is a DDS4 so you can only use the DDS4 tapes A tape holds roughly 1200 images depending of course on your save mode Make sure you bring enough tapes with you If you prefer you are always free to prepare your copies with tar This is not recommended however as tar 1s rather unsafe as 1t copies everything as one single file Also later access to a single file is much more complicated than with FITS tapes where images are stored as indi vidual files As long as the DAT Spooler is not able to write to two DAT drives at the same time we rec ommend to make a security copy of your data with Calar Altos fitscopyx utility Your intermediate results e g from the pipeline can either be copied to tape with the DA Tspooler see Using the spooler from an xterm on page 95 for instructions on how to manu ally copy files or you may transfer them to o2klinux and burn it on a DVD or CDROM t
157. tly both spatially and temporally To obtain flat sky background levels over the wide field of OMEGA2000 a careful measurement of the sky level and shape is mandatory Sky variations constrain integration times and general observing strategy Optical Depth T J H K L E M 1 2 3 4 5 6 Wavelength um Figure 2 Contributors to the atmospheric absorption in the wavelength range 1 to 6u O Cox 2000 Figure 2 shows that water 1s the principal absorber at near infrared wavelengths between 1 and 6 um with very strong bands centred near 1 1 1 38 1 88 2 7 and beyond 6 um CO is the next most important absorber at these wavelengths with strong bands near 2 0 2 7 and 4 3 um and much weaker absorption near 1 22 1 4 1 6 4 0 4 8 and 5 2 um Other trace gases including CH 2 4 and 3 3 um O 3 3 3 57 and 4 7 um and N20 2 1 2 2 2 47 2 6 2 9 and 4 7 um also produce some extinction at these wavelengths b k T d atmospheric i Fi ae emission z 108 BN GBT T TuS i E mm E Ww AP H ih j I 5 iQ EL tw u Bar LUE 5 10 e E TL e eL BBE yo Ne z Um a JZSL SEP gp ax a I em PSI 1 CBR 10 M E L i EE cl L i 1 10 100 1000 Wavelength um Figure 3 Background emission sources see Cox 2000 OH GBT ZSL ZE GBE OH airglow Average OH emission of 15 6 and 13 8 mag arcsec 2 at J and H respectively Ground based telescope thermal emission optimized for the the
158. ulated If the sum save flag 1s set to 0 an updated summation image is written to disk every n average images action flag Specifies the data reduction action 0 do reduction and summation of all images in image catalogue 1 do summation only 1 e the input images are already reduced 2 do single image reduction only 1 e the images are not superimposed sum save flag Specifies what sum images are saved on disk 0 every updated sum is written to disk every n average images I only the final master sum is written to disk 2 the final sum and the real dirty without cosmics removal sum and the difference of the two are written to disk Naming conventions of the sum images sum icat fits for the cosmics cleaned master sum image cut sum icat fits gt for the cut out cosmics cleaned sum ave icat fits gt for the real dirty sum image dif icat fits for the difference image ave sum If intermediate summation results are saved on disk a prefix index 1s added except for first one 2 sum icat fits 3 sum icat fits the last of these frames is cut out e g cut 7 sum icat fits and always con tains the sum of all images LABEL sum kappa sum Cosmics clipping parameter All values above median kappa sum sigma are clas sified as comics and removed kappa sum is a real number LABEL kappa sum cuts min max OMEGA2000 manual doc Cuts for the final frames The descriptor LHCUT
159. und is scaled by differences in box size The ratio of measured to expected count rate is written to the log file Transmission log in the cur rent directory If the star selected is saturated the calculation is aborted and an error message Is issued Currently only the filters J H K and Kp are supported 13 12 List FITS files on disk To list FITS files on disk proceed as follows o Inany MIDAS session change to the path where the files are located a ch dir disSk b o2k DATA o Create an image catalogue of the FITS files create icat raw fits O Gaby OZ List Elle frame List eg cat o2k day 1 raw 1 100 150 170 to list files 1 to 100 and 150 to 170 only This is relatively slow as each file has to be opened and the header in formation to be retrieved o Output will be an ASCII file with name list_file lis and the following information one line per file file ident t NDIT baffle Edd T PETE 2 BEC 25 read mode O2k 2003 09 11T22 17 01 000 fits F0001 fits DQE measurement K PRIME 0 8 5 NO OUT OPEN OPEN K PRIME double corr read O2k_2003 09 11T22_17_22 000 fits F0002 fits DQE measurement K PRIME 0 8 5 NO OUT OPEN OPEN K PRIME double corr read 02k 2003 209 11T22 17 39 000 f1ts 7 F0003 f1ts DQE measurement K PRIME 0 8 5 NO OUT OPEN OPEN K PRIME double corr read 13 13 List FITS files on tape To list a FITS tape proceed as follows o I
160. uted With option macro pause will only get active if a macro is found running Commands macro will be continued by entering the continue command or may be aborted by abort base pwd LYDE Syntax quit CYPE syntax read EVDO syntax repeat type Syntax Repeat for the number the always executed as foreground process inside resets Eype Syntax rmode Lvpe syntax rottab Eyes syntax OMEGA2000_manual doc Write value at offset into the shared memory infopage data 1 value is an int default f wvalue is a float d value is a double s value is a Chat USER pwd Prints actual directory for the save operation UNIX style USER GE Leaves the command shell and kills all subprocesses display gui telgui satcheck If encountered during executing a macro the macro quit just terminates USER read c Read crep images according to the actual cycle type c continous read of crep images until abort read is a background process and should have a after it when used in a macro UNC USER repeat command arg The command is repeat command ENG resets FF oet the number of resets Max only ENG rmode slow fast Set reset mode Max Omega new IRL electronics only Note fast reset mode is not implemented USER potbtab ip x uwrsplevl Tem Start
161. ve to be identical i e no tilt in the fronting You can check the cur rent position of the four trusses with the command ReadFocus in an xterm at the telescope control computer t35 Note OMEGA2000 has no auto guider and totally relies on telescope tracking At the mo ment the pointing model is not ideal This results in drifts of the telescope on the order of 10 per hour Thus one should not run excessively long dither sequences It 1s recommended to re align the telescope after at least one hour of observing 9 The graphical user interface GUI The software handles all infrared cameras at Calar Alto Therefore the observer once having used one system will easily feel at home with the other cameras Slight changes are intro duced only due to different hardware e g the number of filter wheels in the dewar 9 1 Login to the system At any one of the dual monitor X terminals you can log into the fire35 Please choose the CDE desktop at login User o2k Password ask Calar Alto staff The following panels will appear upon login on the otherwise empty screens Left monitor Figure 32 Control panels on the display after login as user o2k The central rectangular blue buttons labelled OMEGA2k and Pipeline on the left and General etc on the right hand screen are meant to select the appropriate desktop for the tasks indicated Once the desktop 1s activated the corresponding tasks are started by clicking on th
162. vity variations and changes in vignetting due e g moving dust specks The central issue in flatfielding nevertheless is to illuminate the detector in a homogeneous way Creating such a homogenous illumination is not trivial Several types of flat fields are commonly in use OMEGA2000 manual doc 6 2 1 Sky flats The twilight sky 1s often used in CCD astronomy to take flatfield images In principle this 1s also possible 1n the near infrared range But depending on sky conditions and the field of view of the detector the sky brightness might vary across the FOV prohibiting a good flatfield 1m age Currently we have no direct experience in this respect with OMEGA2000 The same is true for the median filtered science exposures which are devoid of object signal if the images were dithered However again here variations in sky background and S N considerations are a major obstacle using these data as flatfields One can however hope that 1f sufficiently many science frames are averaged the sky variations are averaging out A procedure to take twilight flats is described in Section 13 3 6 2 2 Dome flats Homogenous illumination of a flatfield screen in the dome eliminates the above mentioned shortcomings However the homogenous illumination of the screen is not easy and often the flattield lamps are too bright Due to the dome geometry it is also sometimes difficult to not illuminate parts of the telescope structure which should be avoided to
163. with scale 2 centred on pixel 1320 912 The lower and upper display levels cuts are at 3500 and 7500 respectively This assumes the 1m age to be in BDF format see below To set the cut levels in terms of local sigma values use back det This command displays the cursor box which should be placed in a region of clean background no stars no bad pixels The cuts are then calculated as median 36 median 106 default To set to other sigmas use back det low high Reading out pixel values from the display J LYCUFS Measuring position and FWHM of an object center gauss The default file type in MIDAS is the BDF format If you want to handle a raw or pipeline produced FITS 1mage you have to append the extension fits to the filename The default command qualifier is ima So comp is equal to comp ima For further information please refer to the MIDAS help GUI m the quicklook window of OMEGA2000 OMEGA2000 manual doc Appendix 13 Glossary To be filled in later Appendix 14 Acronyms used CCD charge coupled device CDS correlated double sampling DSS digital sky survey see http archive eso org dss dss FOV field of view FPA focal plane array GEIRS Generic InfraRed Software OMEGA2000 manual doc 15 References Bailer Jones C A L P Bizenberger and C Storz 2000 Achieving a wide field near infra red camera for the Calar Alto 3 5m telescope Optical and IR Telescope Instrumenta tion a
164. ys a E E F I 3 M m szl E m a m U T 4 l u E a s 7 7 u t i F m 4 Im mas M i u E Figure 54 Focus field at RA 17h Focus at 22h a a J2000 21 58 27 00 8 J2000 20 17 50 E E wx E 1 E P e m 7 gi a i s i z E pk dr a i u ih GPL a 4 BR m F i mk L UM m T H da P Jum ir s E gt m m m i a N c 2 a IUm N p d 3 p P gt a E pd r Ps L an yx gt dr E E E E 4 j m EP x L Ea za F E p u F F E m b s Kg E Pt E I B E f Ly E N 4 i d n x PR m JE t F L E rs T P r t T at a U a x z a ur 1 F F m id s E a a s iate e Wc ud 3 T t a 4 7 i i U T ki EF E i pi A i i i L k E 4 g a a ra s so utu tog e uoto n NOTE I D a T MEL m z F m i z E T a F a a i r i z v d u 3 a r P zj a u Figure 55 Focus field at RA 22h OMEGA2000 manual doc January Elevation of fields M67 Focus 1h 90 80 NGC 1647 70 Focus 60 12h Focus 50 17h 7 Focus 40

OMEGA2000 User's Manual - Max-Planck

Contents

Download Pdf Manuals

Related Search

Related Contents