LMI User Manual - Lowell Observatory
Contents
1. A radial plot from imexamine produced by centering the cursor on a star in ds9 and hitting an r Note from the graph that the peak counts are roughly 800 above sky The output below the plot gives the size of the measuring radius 5 00 in this case the instrumental magnitude 14 94 the total number of counts above sky in the 5 pixel radius aperture 10 581 the mean background 30 02 the peak value above sky 865 6 the ellipticity and position angle 0 07 and 10 respectively the beta value for the Moffat profile fit 5 17 There are then three measures of the fwhm of which I prefer the last For more information see the IRAF help page for imexam In this case the fwhm is about 2 9 pixels or 077 e Examining lines or columns in images It s often useful to plot a single column or line of an image and check the background level or the rms A simple task to do this is implot implot image name gt will display a cut through the middle of the image At the top it will tell you what row line has been plotted An s at two points will tell you the mean and rms between those two points x A 1 230 will plot line 230 A c 512 will plot column 512 x To plot an AVERAGE of 53 rows or columns do a ave 53 before issuing the 1 or c commands e Header contents imhead and hselect 18 We find that it s useful to see what images we ve taken an imhead fits will list the sizes and titles2. Current Azimuth Demand Azimuth Air Mass Target Name Target Time To Set minutes Time To Rotator Limit minutes Current Parallactic Angle Azimuth Current Wrap Current Rotator PA Demand Rotator PA Sun Proximity Moon Proximity Azimuth Error State Heartbeat Time To Blind Spot Exit minutes Elevation Zenith Limit External Target Command Preview p s UTC 16 38 25 2013 01 29 m Current 6 Demand 8 5 Zenith Distance s e Current Elevation Demand Elevation Guide Mode Mirror Cover Time To Blind Spot minutes 1 E Time To Azimuth Limit minutes Julian Date s Rotator Current Wrap o Current Rotator IAA Current Rotator IPA Sun Distance In Blind Spot Target Time To Rise minutes Status TCS AOS A chevrons and the Facilities Summary view bottom e Set up IRAF IRAF provides some very useful basic quick look tools We assume here some famil iarity with IRAF for those not familiar with IRAF we refer you to Section 5 2 Click on the SAOImage DS9 icon in the Dock to start the ds9 image display window In a terminal window type xgterm amp to start up an IRAF graphics window When the xgterm window pops up type cd in it to make sure you re in the home directory Type cl to bring up IRAF Go to tonight s data directory i e cd Imi lt ut date gt what it says on LOUI is your data path
3. E E E 20 20 J bh 3 Tr EE EE Me ED 250 300 350 400 450 250 400 450 500 550 GOU Wavelength nanometers Wavelength nanometers pad a Transmission percent 50 4 Transmission percent e e e 20 20 l I I i 2 i i 1 A poro pa L teo reb Lu BOG FOO BCO ggg YOO Jud o0 1000 Liao Wavelength nanometers Wavelength nanometers 27 100 Transmission percent bod Transmission percent Transmission percent 80 60 40 20 KL 0 495 500 505 Wavelength nanometers 50 a a a ee ee A 1 L A i k BOG 700 Wavelength nanometers DO Lao 1100 Wavelength nanometers 1200
4. This is documented in Section 3 6 2 3 4 Focusing The excellent image quality of the DCT is both a blessing and a curse It s a blessing because well because good image quality is a blessing It s a curse as it behooves the observer to stay in focus Staying in focus with LMI is actually quite straightforward There is a relatively strong dependence on the telescope elevation and mount temperature which are automatically taken into account When you specify a focus value it is actually an offset on top of the baseline value that is corrected for temperature and elevation If the system were perfect you would be able to focus once at the beginning at the night or not even that and stay in focus other than for small relative focus offsets between filters But it s not In practice we see values typically between 900 1000um in the V filter One focus quantum is about 20um in excellent seeing If the seeing is lousy you ll have to use a number like 50 So we recommend the following for good image quality Ask the operator to perform a wavefront at the start of the night This will remove any higher order aberrations in the system It will take about ten minutes and can be performed in twilight If your first field is at a reasonable airmass X lt 1 5 say focus at your field You can focus in any filter we recommend V or R as the atmospheric seeing is always a bit better in the yellow and red than in th
5. U U 10 T de L i F i E i D i 850 900 950 1 000 1 050 Focus Position um Observation Parabolic Fit Fitted Value 936 02 Co Figure 4 Plot produced from the focus run Note that in this case we clearly went through the focus and that the best focus is well defined This will not always be the case 11 Occasionally the focus script will fail Maybe clouds came by and made the star too faint with the adopted exposure time Maybe you picked a star that was a bit too bright or too faint You will notice that no plot has been generated Regardless the last message you see will still say Focus script complete What you need to do is scroll up a bit in the log window and see if there are other messages One of them should say Focus Script Has Succeeded which is good or Focus Script Failed which is bad If you do simply need to repeat the focus run on the same star possibly changing the exposure time or maybe the focus step size or base focus you can easily do this without even taking another test image just go to the Focus parameter menu change what needs to be changed and click on Redo Focus Run But you must have just done a focus run the point is that this will use the identical x and y values for finding the star Note c does a nice job but when the FWHM get tight less than a 3 or 4 pixels say c tends to over estimate the FWHM Some of us prefer to use
6. e Confirm with the telescope operator that the Instrument Cover IC is open Note the IC is a dust cover at the top of the cube It s not light tight so keeping it closed doesn t help biases or darks But you really do need it open before you try gathering photons 1 1 2 Making Sure Things Are Working Whew After all that we should at least take a bias and make sure that everything is copacetic De in excellent order e On LOUI LMI Contol view check that Amplifier is set to A Binning factor is set to 2 Overscan is set to 32 e Take a test bias frame Set the Frame type to bias Click test We note that a number of fun things should now happen in LOUI If they don t see Section 7 The exposure meter will quickly update to 0 0 seconds You will be able to monitor the progress of the chip readout about 22 seconds two ways Right below the exposure meter there is a blue circle This will fill in as the chip reads out In the LOIS Log window you will see the percentage of the readout change Note that there will be a variety of messages in the LOIS Log window As mentioned earlier don t be alarmed when you get a red Error Code NONE upon startup When the image finishes reading out it will be displayed in the image view on the upper left panel e The output of LOIS box will be automatically shown in red above the image area This includes the x y positi
7. to about 9 at U 2 at B and sub one percent at V as shown in Figure 3 This is a characteristic of the annealing process used by e2v and the features flat field out well although the issue at U is complicated by the need to match the color of the flat field to the color of the dark sky Note that at the reddest filters such as the Y ish the chip is nearly transparent and one sees some very ugly stuff in the CCD packaging although the features flat fields out well SkyU U sky flat Skyv V sky flat SkyHa on Ha ON sky flat Figure 3 Sky flats From left to right U V and Ha on Currently there are two options for flat fielding the bright twilight sky which is very blue and the projector screen We ve had very good success with twilights The projector flats differ from the twilights and the dark sky by a few percent due to illumination issues the twilights are right and agree very well with the illumination of the dark night sky on the chip Although the chip has fringe suppression there will be some fringe pattern visible in the reddest filters I i z and Y ish e Try to get on the sky right at sunset Since our shutter is so uniform there is no problem with using very short 0 1 sec exposure times on the sky and this will allow you to get plenty of Hats through multiple filters before stars begin to appear Exposures of 0 05 sec or shorter are not uniform at the 1 level e Ascertain from the telesc
8. 215 inches OIII Andover ANDV13944 U317 02 Construction Interference filter A 5011 7A AA 25 5A 50 Transmission data http www2 lowell edu rsch LMI OIII txt Transmission plot http www2 lowell edu rsch LMI OIII eps 4 751x4 751x0 275 inches Sloan u Asahi Construction 2mm KG3 1mm UG11 4mm fused silica interference film Transmission data http www2 lowell edu rsch LMI u band txt Transmission plot http www2 lowell edu rsch LMI Sloanu eps 4 750 4 750 x 0 277 inches Sloan g Asahi Construction 2mm GG400 2mm BG40 3mm fused silica interference film Transmission data http www2 lowell edu rsch LMI g band txt Transmission plot http www2 lowell edu rsch LMI Sloang eps 4 750 4 750 x 0 277 inches Sloan r Asahi Construction 4mm OG550 3mm fused silica interference film Transmission data http www2 lowell edu rsch LMI r band txt Transmission plot http www2 lowell edu rsch LMI Sloanr eps 4 750 x 4 750 x 0 277 inches Sloan i Asahi Construction 4mm RG695 3mm fused silica interference film Transmission data http www2 lowell edu rsch LMI i band txt Transmission plot http www2 lowell edu rsch LMI Sloani eps 4 750 4 750 x 0 277 inches Sloan z Asahi Construction 4mm RG695 3 mm fused silica interference film Transmission data http www2 lowell edu rsch LMI z band txt Transm
9. At the End of the Night A Quick Look at Quick Look 5 1 LOUI LOUIS Quick look tools 5 2 IRAP quick look 2 64 es 44 e Taking Your Data Away With You Trouble Shooting Acknowledgements and Credit Line Observer Target List How To Reduce Your Data Using IRAF Filter Transmission Specifications 16 16 17 17 19 19 20 21 23 24 1 Introducing LMI The Large Monolithic Imager LMI is the DCT s workhorse camera and contains the largest CCD that can be made using current manufacturing techniques The instrument was funded by the National Science Foundation through AST 1005313 The camera is mounted in the direct through put port on the instru ment cube A Stirling closed cycle cooler chills the CCD to 120 C There are 18 filter slots and currently we have a UBVRI VR and Ha on and off band an OIII A5007 filter the Sloan filters v g r i z and even a UKIDSS WFCAM Y ish filter with an extended red cutoff good luck with that The CCD is run using a Generation III Leach controller There are three fundamental software systems that the astronomer should be aware of at present Each piece of software runs on a different computer although the astronomer interfaces with them through the astronomer computer a dual screen Mac Pro named baggins e LOIS Lowell Observatory Instrument System is the guts level system that actually runs the CCD controller setting the micro code generating the
10. Exposures 1 Tel Binning Factor 2 1 Analysis Result Frame Type object 3 Over Scan 3 Value L t Object Title Image X Y 365 205 FITS Comment 1 FITS Comment 2 Lower Filter Wheel FW1 Upper Filter Wheel FW2 5i Enable Focus Offset M Synchronized Moves initialize Move Home Lower Check Status Kill Commands AOS Focus Command 02 C1 Good DC Good TCS Offset Commands SubFrame Definition Analysis Definition vi g L3 E Console Z Console x bel 4 Be ree initialize Consoles Log Level DI info 91 O exposure 0 0 0 0 0 0 seconds 0 I O Total 0 00 GB Used 0 00 GB Available 0 00 GB Lm st GDR JOE On TCS AOS DOME The LOUI screen upon startup By default LOUI comes up in the dashboard perspective upper left and image view 2nd row down on the left Figure 2 The Information view top with the later having its sections expanded by clicking on the OORA Observer Massey Skiff Pugh Lowell Observatory Path 1mi 20140914 File Name Imi 0011 fits Total Used Available 976 27 GB 509 79 GB 466 48 GB Set Standard Image Path amp Observer Reset Observer Name Massey Skiff Pugh Observer Affiliation Lowell Observatory Set Custom Image Path Sound Effects a TE ss Custom Personal_ Developer Wil Dashboard MA Image Camera Telemetry x gi LST Current e m Demand a Hour Angle
11. IRAF in this case In the IRAF window do the following e display test fits 1 imexamine e Position the cursor over a star in the ds9 window and hit r You ll have a nice radial plot of the star The fwhm will be the last number shown in the graphics window e LU 66 99 e Type a g to leave the graphics window and another q in the ds9 window to quit imexamine Note to the IRAF savy Yes you can use imexamine imagename 1 directly however if the imagename matches what you ve just previously displayed IRAF will fail to display the new image So if you are trying to examine a new test fits after a previous test fits things will get rapidly confused 3 5 Observing Once you are satisfied with the focus begin your exposure set image type to object and specify the number of exposures and the exposure length When the pointing model is working well you can track for several minutes without appreciable smearing even without guiding Note that you can always stop a single exposure with the Abort button or terminate a series of exposures early using the Stop Series button Figure 1 LOUI provides some very valuable guidance to you as to whether or not the telescope is ready Note that at the bottom of LOUI screen see e g Figure 1 the words TCS AOS and DOME Wait for these to all be green before starting your exposure These indicate respectively that the telescope is in position that the secondar
12. S141 01 Construction 2mm GG495 2mm S8612 Transmission data http www2 lowell edu rsch LMI V txt Transmission plot http www2 lowell edu rsch LMI V eps 4 752x4 752x 0 157 inches R Kron Cousins Andover ANDV12686 5136 01 Construction 2mm OG570 3mm KG3 Transmission data http www2 lowell edu rsch LMI R txt Transmission plot http www2 lowell edu rsch LMI R eps 4 751x4 751x 0 198 inches e I Kron Cousins Andover ANDV12687 5147 01 Construction 2mm BK7 3mm RG9 Transmission data http www2 lowell edu rsch LMI I txt Transmission plot http www2 lowell edu rsch LMI I eps 4 752x4 752x 0 196 inches e HaON Andover ANDV12688 S183 01 Construction Interference filter 6564 9A AA 30 1A 50 Transmission data http www2 lowell edu rsch LMI HaON txt Transmission plot http www2 lowell edu rsch LMI HaON eps 4 753x4 753x 0 215 inches HaOFF Andover ANDV12689 S138 01 Construction Interference filter 6459 1A AA 114 6 5096 Transmission data http www2 lowell edu rsch LMI Ha0FF txt Transmission plot http www2 1owell edu rsch LMI Ha0FF eps 4 753x4 753x 0 215 inches 24 VR Andover ANDV12690 S160 01 Construction Interference filter 6091 7A AA 1763 9A 50 Transmission data http www2 lowell edu rsch LMI VR txt Transmission plot http www2 lowell edu rsch LMI VR eps 4 753x4 753x 0
13. best idea muRA proper motion in RA mas yr Note that this is actually ua x cos which is what most catalogs and SIMBAD provides muDEC Proper motion in Dec mas yr magnitude Magnitude The option to include magnitude is in case the observer wishes to sort the table based on brightness It is not used by the TCS dRA non sidereal tracking rate in RA in units of arcseconds hour dDec non sidereal tracking rate in DEC in until of arcseconds hour rotatorPA The rotator position angle in degrees With the rotatorFrame Target the default angle of of 0 results in LMI having images whose columns are rows are aligned with the cardinal directions as given in in Section i e N up and E to the left when using the default amplifier A 21 Setting this the rotator PA to 30 will change this orientation by 30 from north through east In rotatorFrame Fixed mode this angle is instead the mechanical angle of the rotator ignoring the sky orientation This mode is primarily an engineering mode e rotatorFrame Valid choices are either Target or Fixed without the quotes The use of Tar get the default is the only reasonable one for normal observing The fields should all be separated by at least one space The columns do not have to line up but extra spaces can be inserted if it makes you happy Note in constructing this file make sure you use a text editor such as vi or emacs Do not use Text Edi
14. of the previous night Click on the Exit LOIS button at the extreme upper right of the screen e Restart LOIS In terminal window ssh obslemi lemi The password is on the whiteboard Type st to confirm that LOIS is Not Running If instead it lists a 5 digit number PID next to LOIS repeat the previous steps click on Stop Series and then Exit LOIS and check with st again Type lois amp to start LOIS You will see some messages about no authentication appear ignore them We recommend that you leave this window open in order to catch any error messages in case of problems e Check that JOE is on You should see JOE On at the bottom of LOUI If it hasn t been restarted you won t be able to move the filter wheel get good FITS headers and so on You can always ask your operator how JOE is doing normally the operator stops and restarts JOE at the beginning of each night e Restart LOUI Kill LOUI by clicking on the little red Mac close the window button on the upper left of the LOUI screen Restart LOUI by double clicking on the LouiStartup icon on the desktop This will not only start up LOUI but will reset the time precisely You ll be asked for the lmi password it is on the whiteboard If you have to restart LOUI later in the night you can skip this step and just click on the LOUI icon itself Click the green initialize LOIS in the
15. that has the same image type binning etc that you want to use 5 Remember what we said about relative vs absolute offsets above in Section 3 6 1 Well if you use xi and eta to specify offsets these will be absolute and if the last one you specify isn t 0 your pointing is going to be off until someone realizes this and explicitly clears the offsets There are several things you can do about this but the easiest one to describe is to just make sure your last offset has xi 0 0 and eta 0 0 Full documentation can be found at http jumar lowell edu confluence display DCTIC Automated Functions 4 At the End of the Night There are a few things we d like you to do before you call it a night e Remind the operator to close the instrument cover e Gracefully log out of IRAF type logout in the xgterm window You might even want to close the window e Kill the ds9 display e Finally we d like you to leave a lois task running that continues to monitor the temperature of the CCD e On LOUI go to upper right corner and click on Get Temp Note this will tie up LOIS and any effort to do anything else such as take a picture will be queued up until the end of the world If you want to end this without actually killing lois simply click on stop series on the LOUI console 5 A Quick Look at Quick Look As you observe you ll of course want to be keeping tabs on how things are going There are two basic ways
16. the electronic version under OpenOffice on Linux systems 3 2 Moving the filter wheel The filter wheel has absolute encoding thus it is not necessary to home the filter wheel If JOE is running the camera GUI should display the location of the filters D 3 C 3 for example It will also show whether the detent is in GOOD or not BAD Very occasionally there will be a glitch try clicking Check Status If that doesn t clear the problem click Home Lower and then Home Upper to home the wheel If that doesn t work it may be necessary to initialize the motor controller card this is a rare circumstance that occurs only if the cards have been powered off during the day To change filters click on the filter name you want When you re ready to move it click on move Wait until you get a valid reading below the filter wheel and the detent reports GOOD before starting your exposure 3 3 Moving the telescope into position There are currently three ways for the astronomer to cause the telescope to move into position 1 Give the operator your coordinates either on paper or by shouting across the room 2 Construct a simple text file ahead of time and load it into the Target Observing List in order to select coordinates to send to the telescope operator The latter is detailed in Appendix A 3 Construct a Slew Pattern List that includes your targets exposure times and so on
17. to do this I like to use a combination of them 16 5 1 LOUI LOUIS Quick look tools e Every time an image reads down you will find the peak counts average counts and standard deviation displayed in brown These come from a 100x100 box at the center e Moving the cursor around in the image area will also show x y and value If this isn t working make sure that the image display is active by clicking in the imager window e Typing a c with the cursor on a star will give the x and y centroid the the FWHM a magnitude and the peak counts c keystroke invokes LOIS phot command with a reasonable set of defaults Note that this can only be run when LOIS is idle otherwise the command will simply queue If you are unsure what is what simply positioning the cursor over the string of numbers will identify the output LOUI provides additional quick look options which we describe here but there s an important caveat in order to display the large LMI images LOUI uses an internal binning actually sampling You can see the LOUI Binning Factor LBF listed in the image view That means that most LOUI quick look functions such as pixel dumps line and column plots are not actually showing you the values for all of the pixels but likely every other pixel You will see Pixel Dump and Line Profile tabs next to the LMI Control and User Button at upper right e PixelDump This allows one to get a pixel
18. upper right corner of the GUI A red Error Code NONE will appear in the log window at lower left this message may safely be ignored At the lower right you ll see the information view exposure time counter marked in blue exposure 1 1 0 0 0 0 seconds 100 at start up Figure 2 upper Within this panel scroll down below this until you can enter the Observer Name and Observer Affiliation section Fill these out and click Set Standard Image Path amp Observer Right below the exposure time counter the Observer Name and affiliation should appear Right below that is the image path name Make sure that it says Imi ut date where ut date is in the form 20140201 If not it can be set explicitly by clicking on the chevron Set Custom Image Path but this is highly unusual and you probably have the operator call for help You can have sounds happen at the end of an exposure and or at the end of the read out and or at the end of a series of exposures Open the chevron labeled sound effects below the data path By default LOUI is silent thank goodness Note that you can also turn on a sound effect for exposures that are suddenly blocked due to missing telemetry or other issues that might impact the FITS header see Section 7 Check that LOUI is talking to the filter wheels Below the picture of each wheel it should say something like D C 1 and Good The D value is the demanded posi
19. 10 8 Pos 3 B 18 Pos B 10 Pos 5 B B Figure 6 A sample dither pattern In this particular example the user is specifying the title name and the offsets and nothing more Options include e title This will be treated the same as the Object name in the LMI Control view e RA and DEC Only J2000 0 coordinates are allowed e exposureTime The exposure time in seconds This must be present e numExposures If this is not specified it will default to 1 14 title true ra true dec true exposureTime true numExposures true filter true muR A Talse mudec false epoch Talse dRA Talse dDec false rotatorPA Talse rotatorFr Sue Nun xietrue etastrue commentefalse conmmand ptiansetrue E Fieldl Posl1 81 34 15 BB8 20 49 53 4 10 IV DH Slew Fieldl Pos2 81 34 16 88 30 49 53 4 18 1 V 18 6 Dither Fieldl Pos3 81 34 15 BH 4318 49 53 4 10 1 V 8 18 Dither Fieldl Pos4 81 34 16 BB8 30 49 53 4 10 1 V 18 B Dither Fieldi Pos5 01 34 16 808 320 49 53 4 18 1 V 10 10 Dither Field2 Posl 81 34 12 15 30 43 45 9 100 1 V B Slew Field2 Pos2 01 34 12 165 38 43 45 808 188 1 V 18 B Dither FieldZ Pos3 81 34 172 15 30 432 45 9 100 I V D 18 Dither Field2 Pos4 81 34 12 16 318 43 45 9 1808 1 V 18 B Dither Fieldz Pos5 81 34 12 16 38 43 45 9 188 1 V 18 18 Dither iep Figure 7 A sample combined slew and dither pattern In this particular example the user is specifying the title name the ra and dec the expos
20. Dec false epoch false dRA false dDec false rotatorPA Talse rotatorFr ameefalse xiefalse etaefalse commentefalse command ptionefalse x Fieldl 81 34 15 8B 38 49 53 4 1B 3 V Fieldl 81 34 16 8B8 38 49 53 4 20 5 B Field 81 34 12 16 38 43 45 9 73 NM Field 81 34 12 15 38 43 45 9 14 5 B Fields 81 33 47 78 38 35 58 1 JB 3 V Fields 81 33 47 79 38 35 59 1 Ag 5 V Fieldd 81 33 22 789 38 32 47 2 za 3 V Field4 81 33 22 79 38 342 47 2 AB 5 B Field5 80 45 17 89 41 52 09 5 15 3 V Field5 88 45 17 89 41 52 09 5 38 5 B Field6 88 44 25 83 441 58 198 4 15 3 V Field 88 44 25 883 41 58 19 4 38 5 B Field 88 45 17 55 441 39 22 0 i2 A V Field 88 45 17 55 41 39 27 0 50 5 B Fielde 00 42 19 1868 41 28 09 4 58a V Field 88 42 19 1B 41 28B 09 4 180 5 B Te Figure 5 A sample slew pattern In this particular example the user is specifying the title name the RA and DEC the exposure time the number of exposures and the filter Finally let us see what a really complicated file might look like we go to an object perform some dithers and then go to a new object and perform some more dithers An example is given in Figure 7 Stitle true ra false dec false exposureTime false numExposures false filter fals e nuRAsfTalse nuDe csfalse epoch false dRA Tal e dDec false rotatorPAsfalse rota torFrame false xi true eta true comment false command ption false a Pos 1 18 6 Pos 2
21. FITS header and doing all the heavy lifting It runs on the computer lemi e LOUI LOis User Interface is the means by which the astronomer controls the exposure defining the type of exposure exposure time setting the filter in other words it s the user interface It runs on the Mac Pro astronomer s computer baggins e JOE Java Operator Executive is a software controller that needs to be running in order for LOUI and lois to talk to the the filter wheel and obtain telemetry from the telescope control software for header information JOE runs on the computer wait for it joe Generally the astronomer doesn t have to worry about this one other than to be aware that JOE needs to be alive in order to change filters In addition the astronomer will probably want to run IRAF and ds9 to perform real time evaluation of the images Sound confusing Let s walk though the basic start up 1 1 Getting Started at the Beginning of the Night 1 1 1 Start Everything Running e Cleanly exit LOIS At the two screen Mac Pro under the right most window in the control room identify the LOUI screen it s almost certainly been left running and will be occupying most of the left screen See Figure 1 Click on the LMI Control tab just to the right of the middle near the very top of the window and then click on the Stop Series button This will terminate the temperature taking sequence that was started at the end
22. The Large Monolithic Imager User Manual Philip Massey November 22 2015 About this manual Although this document is a pdf you should be able to click on references to section numbers and figures that are marked in red If it says we refer you to Section 5 2 clicking on the 5 2 will take you there To return you need to do a previous view On a Mac in Preview this is Go Back while on a Mac in Adobe this is View Navigation Previous Please let me know what s missing and what could be made clearer in the manual phil massey lowell edu Fun Facts e2v CCD231 6144 x 6160 15um pixels 92 16 mm x 92 40 mm The spec sheet for the chip can be found at http www2 lowell edu rsch LMI G1 pdf FOV 1273 x 1273 Scale 07120 pixel unbinned 07240 pixel binned 2 x 2 Gain 2 87 e ADU amp A but other amps similar Readnoise 2 1 ADUs about 6 2 e amp A but other amps similar Normal operating temperature 120 C Linearity Thanks to improvements made in August 2014 all 4 amplifiers are now linear to lt 1 over the full data range Count rates at U B V R I 20th at an airmass of 1 0 integrated over a stellar profile U 60 e sec Sloan u 115 e sec 610 e sec Sloan g 715 e sec 590 e sec Sloan r 680 e sec 575 e sec Sloan i 500 e sec 410 e sec Sloan z 310 e sec 890 e sec Y ish 19 e sec HaON 14 e sec HaOFF 65 e sec OIII 14 e sec To compute exposure times use the Exposure Time Calculator ss ED E Filte
23. allows you to execute such a string of commands a Slew Dither Pattern where each setting is a successive command line in a text file The function is very versatile and the choice of parameters to be specified in the command lines is set by the user in the top control line of the text file The operations specified in the pattern file act concurrently in the sense that once the shutter closes and the CCD begins to read out the specified telescope and filter motions for the next exposure are initiated and are likely to be complete by the time the current exposure s FITS file is written Guided offsets are supported with this function but the maximum that will work for a star in the center of the guide annulus is 90 arcsecs and smaller values will fail if the guide star your operator has selected is not located optimally So make sure your operator knows the details of dithering plans Let us consider the simple case of wanting to slew to a variety of objects An example is given in Figure 5 Now consider the somewhat different case of a dither pattern An example is given in Figure 6 Note that the sequence ends with a 0 0 offset This is because the offsets are absolute and are not cleared therefore ending with a non zero offset will affect the pointing of all subsequent targets until explicitly cleared See 3 6 1 13 Xtitlestrue rastrue d cstrue exposureTimestrue numExposures true filt retrue muR A false X mu
24. any arcseconds you d like to move left right or up down on the image To an astrometrist these would be known as standard coordinates and they are usually referred to as and 7 See for example http nexsci caltech edu workshop 2005 presentations Girard_coordinates pdf But if you re just trying to shift things left and right on the image you want to be using tplane Enter the units as arcseconds remembering that each pixel is 07240 when binned 2 x 2 simple In simple coordinates you tell the telescope to offset a certain number of time seconds in RA and a certain number of arc seconds in DEC This is most useful perhaps if you want to move between two targets whose coordinates you know such as an offset star and a target when doing spectroscopy pa In pa you specify an offset in polar coordinates a radius in arc seconds and a position angle in degrees No one has yet figured out why we have this option 3 6 2 Dither Patterns and Slew Patters What if you knew that once you were happy and focused you d like to move to object A take some exposures move to object B take some exposures and so on If you were doing this over and over it should be nice to be able to do this automatically Alternatively you might want to perform some dithers on a particular target or just take groups of exposures with different filters and exposure times and the telescope fixed We now have a function that
25. basic combination of bias frames and flats after overscan removal e Create a backup directory called Raw mkdir Raw e imred e ccdred e setinstrument direct You ll be thrown into the parameter editor for ccdred Change backup to Raw and exit with a CNTL D You ll then find yourself in the parameter editor for ccdproc For now set images lmi fixpix no overscan yes trim yes zerocor no flat cor no illumcor no biassec 3100 3124 3 3079 trimsec 30 3094 3 3079 interact no func tion chebyshev order 1 e Create a master bias frame by running zerocombine Imi fits process yes e epar ccdproc and turn zerocor to yes and zero Zero e flatcombine lmi fits Be sure to examine the result FlatX frames to make sure that any stars present in your sky flats have disappeared 3 Now process all of your images e epar ccdproc and turn flatcor to yes and flat Flat e ccdproc lmi fits 23 C Filter Transmission Specifications e U Andover ANDV12683 5136 01 Construction Imm UG 1 1 25mm 8612 3mm WG 305 Transmission data http www2 lowell edu rsch LMI U txt Transmission plot http www2 lowell edu rsch LMI U eps 4 752x4 752x 0 206 inches e B Andover ANDV 12684 5138 01 Construction 1mm GG385 2mm S8612 1mm BG12 Transmission data http www2 lowell edu rsch LMI B txt Transmission plot http www2 1lowell edu rsch LMI B eps 4 752x4 752x 0 157 inches e V Andover ANDV12685
26. dump of the image in the image view You place the cursor in the image and hit p But be warned these are sampled values because of the additional sampling that LOUI does for the display so the peak intensity of a star won t be correct except by accident and similarly a bad column or other defect may escape notice Note also that the x and y values are off by a factor of 2 due to the LOUI Binning Factor This is a known bug and will be fixed soon e LineProfile This allows the user to make line and column plots a Il in the image display will display just the region that is expanded in the image view while an L will provide line and column plots of the whole image But again be warned because of sampling you re not seeing all the pixel values Note also that the x and y values are off by a factor of 2 due to the LOUI Binning Factor This is a known bug and will be fixed soon 5 2 IRAF quick look Because LOUI is sampling the images only the output of phot invoked by a c and box auto matically invoked when an image reads down are telling you the complete truth the other LOUI specific quick look routines are giving you the results from sampled images For that matter c also tends to overestimate the FWHM when the values get small lt 3 Thus for critical work I like to use IRAF Some users are probably well familiar with IRAF others not Here is quick guide e Displaying and analyz
27. e far blue Note that by checking the box that says Enable focus offsets the focus will change by a small amount as you change filters this is based upon our on sky measurements and the ZMAX predictions of the focus difference between filters Next to the filter controls you ll find AOS Focus Command Open the chevron enter 950 if the V or R filters are in place and click on the Send button If you plan to focus is some other filter we recommend first homing both filter wheels setting the focus to 750 and then going to your filter making sure that Enable focus offsets is indeed checked In this case note the new focus value displayed at the bottom of the Facilities Summary when the filter is in place as you ll want to use this as your base focus value Take a 3 sec image using the test button Look at the image display after the image reads down Measure the approximate fwhm by clicking on the display window and then typing a c when positioned over the star You will see the x and y centroid displayed along with the peak counts average counts and RMS Find a star where the peak counts are 6 000 30 000 ADUs On the second row of the Image View over on the left side of LOUI right above the image area pull down the menu from the arrow next to the word Focus Select Focus Parameters Change the exposure time to 3 seconds and the base focus to 950 or whatever was set when you chan
28. ged to your filter if not using V or R if need be If everything is working right these should come up as the default Now select Mark amp Initiate Focus Run Click on the star A small image will be taken centered on the star you selected Next a focus run will then be made consisting of 9 exposures centered on the base focus and moved by focstep When it s done the log will report Focus script complete A few seconds later be patient a plot will pop up showing the widths as a function of the focus values See Figure 4 If you re happy with the value displayed in the text box click OK and the value will be sent to the AOS as the new focus value Check that the focus has been set to the new value by looking at the bottom of the Facilities Summary Take another short 3 sec test frame and confirm that the full width at half maximum FWHM of a few stars are reasonably good The easiest way to do this would be to put the cursor on a star in the image display and type a c 10 FWHM pixels Selecting OK will send the value in the text box to the ADS and Cancel will send the base focus value ie Focus Run Values i TITTITITITITITT ao mt a a a a FATT m U D pre og e bee see eee eee ee nn SEE EEG pl e mmm mm mm mr ome pr ome mr rer e mr e U D i E i i i 2 0 R wb el 1145 4 mem mm w Mee mam ees ae en eee ee ee en Kale ee lee ey P Ic AG sumom ee smo smo lr NW i U
29. ing images The most useful command in IRAF for checking on images is the task imexamine Here are some simple ways to use it You can also do a help imexamine at the IRAF prompt to learn a great deal more First display an image in ds9 by doing display lt imagename gt 1 where lt image name gt is something like 1mi 0032 You can then adjust the contrast and brightness by holding down the right side of the mouse and moving the cursor in ds9 If that doesn t work sufficiently you can be specific about the data range that you are windowing about by doing a display 1mi0032 1 zrange zscale z1 900 z2 2000 in order to send the data range 900 to 2000 to ds9 17 To check the average value and rms in a 51x 51 box near the cursor use an m To determine the radial profile and full width at half maximum fwhm of a star image position the cursor over the image of the star and type an r The fwhm is the last value shown on the graph This also displays the total number of counts above sky background See Figure 8 66a You can do a line plot or a column plot using I or c But this is not terribly useful as you can t do much by way of statistics when you do We prefer to use implot see below Recall you can always do a while in imexamine to see a full list of commands 6699 To quit type a q eoo X irafterm 3 4 Ta dt li e H 8 32 43 rue TOTNM TR Figure 8
30. ission plot http www2 lowell edu rsch LMI Sloanz eps 4 750x4 750x0 277 inches Y ish Asahi Construction 4mm RG695 3 mm fused silica interference film Transmission data http www2 lowell edu rsch LMI Y band txt 25 100 80 Transmission plot http www2 lowell edu rsch LMI Y eps 4 750x4 750x0 277 inches 100 100 U ANDV12683 B ANDV12684 80 80 g E G Q o o o o o 60 9 60 60 Bi amp g g g o o o un n n E40 g 40 ga n n n g i a d E E he be Em 20 20 20 0 0 0 300 350 400 450 300 400 500 600 450 Wavelength nanometers Wavelength nanometers 100 100 100 R ANDV12686 I ANDV12687 80 80 80 D D EN E E E o Q Q o o o 60 s 60 9 60 d d g g amp o o o n n n E 40 E 40 S 40 ul n n A amp e E E be be be E e 20 20 20 0 0 e 0 500 600 700 800 900 700 800 900 640 Wavelength nanometers Wavelength nanometers 26 V ANDV12685 500 550 600 Wavelength nanometers HaON ANDV12688 650 660 Wavelength nanometers 650 700 670 100 Transmission percent 100 HaOFF AN VR ANDV12690 80 80 60 60 40 40 Transmission percent 20 20 0 0 620 640 660 680 400 500 600 700 800 Wavelength nanometers Wavelength nanometers 100 pag Sloan g Se n i ag ag s P E sa u 80 E e k B a D Kul E m E 40 E 4 E E c 5 d
31. ked up once an hour thanks to the Mac s Time Machine and in addition we do back up the data off site Thus while we can t guarantee we can retrieve your data for you a year from now it s not unlikely either Still the process of retrieving data after the fact is labor intensive and cumbersome and we recommend you take responsibility for your data 7 Trouble Shooting So far our experience with LOUI lois as implemented at the DCT has been that it has been remarkably trouble free Here are a few of the more common gotchas e In order to avoid unpleasant surprises LOIS has been configured so that a number of conditions result in the exposure being blocked For instance if the telemetry stream coming from the telescope is missing some information when you go to take the exposure you ll be issued a warning in the LOIS log window and the exposure won t happen However as the message tells you if you are insistent and press go a second test the exposure will happen However if the condition leading to the block still prevails after you have taken the exposure anyway you will get red messages in the LOIS log at the end of the exposure traffic saying something like The telemetry is still bad These messages will disappear at the next exposure you take after the problem is resolved We thought that a good way of getting your attention might be to not let the exposure proceed but after that what you do is up t
32. me it is being used 15 2 The format of the meta data at the start of the file must be specified exactly as in the example shown in Figure 5 your only option is to change things from true to false or false to true with the above restrictions Note especially that either RA DEC or xi eta must be set to true If you are using this function to simply switch between filters without any telescope motion desired i e you re moving the telescope to your target external to this pattern then use xi eta and specify these as zero s in the input files as this will circumvent any telescope command from being issued 3 It is absolutely essential that you do not attempt to interact with the filter wheel or otherwise mess around with the exposure parameters using the LMI Control view once the Slew Pattern has started Very Bad Things May Result Do NOT expect the filters shown on the LMI Control view GUI to reflect what is going on with the instrument once the Slew Pattern is activated instead the Slew Pattern view will show what filter is in use 4 The slew pattern will use whatever set of image parameters were used for the previous exposure So if your last exposure was a bias frame all of your exposures will be wind up being a bias frame even if you ve specified the exposure time Before you start the slew pattern make sure that you have at least taken a test exposure from the LMI control view
33. n be used during one session and each file would be loaded into a separate tab The process of sending the target to the TCS is a 2 step process First a target is selected from the table The data is loaded into the upper view for a final check by the observer It can be sent to the TCS as a science target by pressing the button Issuing this command can result in either the telescope moving immediately to the target or simply loading the target into the preview pane for the telescope operator s approval The behavior can be selected on the TCS s UI and cannot be controlled by the observer from the app The selection is persistent until changed by the operator You can check which mode the system is in by looking at the External Target Command label which will either say Preview the operator checks or Direct the telescope just goes there Note that we provide several observing lists in the PhotStds folder on the desktop e AA2014_ubvri tls Astronomical Almanac for 2014 list of UBVI standards section H which is basically the list from Landolt 2009 This is there in case you need it but most observers will prefer landolt09 22 e clem13 tls Clem amp Landolt 2013 Faint UBVRI standard star fields e landolt09 tls Landolt 2009 UBVRI photometric standards around the celestial equator This is the preferred list Finding charts are available locally on baggins by going into the landolt09 subdirectory i
34. n the PhotStds folder e landolt02 tls Landolt 1992 UBVRI photometric standard stars in theMagnitude Range 11 5 lt V lt 16 0 around the celestial equator This is available if you need it for a particular reason but most observers will preferred landolt09 tls e clem07 Clem Vandenberg amp Stetson 2007 Secondary standard stars for the u g r i z photometric system e hbstand tls Farnham Schleicher amp A Hearn 2000 The HB narrowband comet filters standard stars and calibration B How To Reduce Your Data Using IRAF Here is a fairly complete list of everything I did to reduce some recent images I m assuming you ve reduced a bunch of images with IRAF before If not please have a look at http iraf net irafdocs ccduser3 1 hselect Imi fits Limagetyp filters exptime title This allowed me to check that the filter values were fine that the images were what I thought they were and so on If you ve used sky flats as your primary flats as recommended then they need to have image types of DOME FLAT rather than SKY FLAT You can readily change this by hedit imagename fits IM AGETYP DOME FLAT up ver show If that offends your sensibilities you can do a copy ccddb kpno kpnoheaders dat Imi dat and then edit Imi dat so that an imagetyp of SKY FLAT translates to a flat and not an object If you do this you must reset instrum to Imi dat in ccdred 2 Do the
35. o you e If nothing seems to be happening when you go to take data with LOUI maybe LOIS is not running or else is busy In a terminal window do an ssh obslemi lemi password on whiteboad unless you are already logged in Do an st Does it list LOIS as busy If so click on Stop series This 19 should get LOIS to stop doing whatever it is that it s doing If that doesn t solve the problem click on Exit LOIS and check with an st on lemi that LOIS is not running Restart it by doing a lois amp Do a new initialize LOIS on LOUI e If you re like me you ve pulled the various views onto the desktop at some point to see if you liked the arrangements and then failed miserably to put them back where they belonged You can put things back to normal by going to window Reset Perspective at the top menu bar when LOUI is active e You ve started things up but nothing but nothing seems to work and all you get are scary looking red error messages or pop up windows Take a deep breath Did you remember to hit the green initialize LOIS button in the upper right corner Give it another shot If that fails I would ssh obslemi lemi in a terminal window do an st and see if kill lois and restart it It can t hurt Pd also close LOUI reopen it and do initialize LOIS again My experience is that the system behaves very solidly but because the start up is complex it s eas
36. of each image If you d like to substantiate that what is going into the headers is what you need to be going into the headers always a good idea select an image and do an imhead lt imagename gt 1 The l tells it to make a long listing including all of the FITS key words Just want to see what a single value is from your header Do an hselect lt imagename gt exptime yes in order to see the value for the exposure time Or you can list such values for all images hselect fits I exptime yes The I prints out the name of the image 6 Taking Your Data Away With You Remember those awkward days of writing exabyte or DLT tapes or spending half an hour while you burn a DVD What I find works really well is one of the following e Bring an external USB disk with you to the telescope I have a fine 0 5TB drive that fits into my shirt pocket and now a days costs about 50 Once you ve plugged it in to baggins USB port just do a cp Imi lt ut date gt to your drive e Alternatively simply sftp to ImiQbaggins password on the whiteboard cd Imi lt ut date and get fits To keep in mind the storage capability and transfer times consider that each 2x2 binned image is about 19 3MB If you took a 100 images in a night likely this would be 1 9GB If you took 1000 unlikely that would be 19GB So this is hardly big stuff If you haven t binned the storage requirements are 4x larger All files do get bac
37. on the maximum number of counts the average number of counts and the standard deviation Check that the average counts are about 1100 and the standard deviation is about 2 5 ADUS on this bias frame e You can also move the cursor around in the image display window to see the counts at various x and y positions e This is probably good time to make sure that the images are indeed in the right directory and that the headers look reasonable In the IRAF window do an ls I and you should see test fits with the current date and time You can do an imhead test fits 1 to see the headers If the Telescope Control System tcs is up and running these should all be populated with reasonable values 2 Calibration We ve gotten good results with the following 1 Biases There is a significant 20 30 ADUs turn down in the bias frames on the left so subtracting an average bias is a good idea Here s what I do to obtain a suitable measurement of the bias structure e The instrument is pretty light tight but if the DARK filter is available put that in place To move to a particular filter click on the filter name then click on move e Set the frame type to bias and the Number of exposures to 10 Hit Go 2 Flats This chip is quite well behaved but there is a 5 illumination function from center to edge on the broad band filters plus a very interesting quilted pattern at shorter wavelengths amounting
38. ope operator that the mirror cover is open the dome shutter is open and that you are in a comfortable place for twilight flats The Chromey spot is a region that is most uniform i it s about 1 5 hour east and a declination of 25 e Start with the bluest filters if broad band or the interference filters if using them and take a 0 1 sec exposure Evaluate the counts after it s read out By moving the cursor around in the image window you can see the counts If it s 65000 then the exposure is saturated and it s no good Raw counts of 4500 ADUs will give you 1 statistics e After each exposure while the chip is reading down offset the telescope by 20 arcsec using a tplane relative offset of 20 You ll find the control for this directly under the filter wheel GUI open the chevron that says TCS Offset Commands Make sure you use Relative and not Absolute e Keep increasing the exposure time to maintain counts of 4 500 50 000 for each exposure offset ting between each exposure 3 Observing 3 1 Logs Many astronomers like to take logs as a backup to the header information Larry Wasserman has kindly provided paper logs you should be able to find these in the control room near baggins Alternatively you can download an editable log sheet that comes from Las Campanas Observatory courtesy of Sergio Castellon Note this shows up properly on Macs for mysterious reasons there s some problems with
39. r specs can all be found in Appendix C Typical transformations with an instrumental mag of 25 corresponding to 1 ADU sec u U 1 275 0 50X 0 112 U B b B 1 073 0 25 X 0 039 B V v V 0 919 0 15 X 0 028 B V r R 0 854 0 10 X 0 029 V R i 0 441 0 07 X 0 021 V I Orientation within 0 1 with Instrument Alignment Angle IAA set to 18592 ask operator to set Amplifier A N is up E is to the left Amplifier B N is up E is to the right Amplifier C N is down E is to the left Amplifier D N is down E is to the right Readout plus prescan times Unbinned 73 sec 2 x 2 binning 24 sec 4 x 4 binning 10 sec Recommended settings Amplifier A Binning 2 x 2 Overscan 32 Computers baggins astronomer work station runs LOUI login Imi password on whiteboard lemi runs LOIS itself login obslemi password on whiteboard 2 Contents 1 Introducing LMI 1 1 Getting Started at the Beginning of the Night 8 ra 1 1 1 Start Everything Running 1 1 2 Making Sure Things Are Working Calibration Observing E 4 229 535 3y 3 5 3 2 Moving the filter wheel 3 9 Moving the telescope into position J FN 533 os o9 xe eee x wa D eeneg s s svak e 3 6 Some Useful Observing Tips 3 6 1 Offsets 1 sma dw eee dow 3 6 2 Dither Patterns and Slew Patters
40. serving list and send the object coordinates to the operator Full details can be found at http jumar lowell edu confluence display DCTIC Observer Target List The format of the file is similar to that of the Slew Dither files at the top of the file there should be a line that specifies what information will be included A simple example is shown in Fig 9 Note that if you have an Observer Target List file that was prepared before the introduction of the Metadata format it should still work Ktitlestrue ra true decstreu epoch false muRA false muDecsfalse magnitue false dRA false dDec false rotatorPA false rotatorFrame false Field 1 1 34 16 88 38 49 53 4 Field 2 801 34 12 16 30 43 45 9 Field 3 1 33 47 79 438 35 59 1 Figure 9 A simple observer target list Only the object name RA and DEC are specified the minimum that is required The possible fields for inclusion are title This needs to be surrounded by double quotes and will be sent to the TCS as the science target name It cannot be blank REQUIRED ra The J2000 right ascension in hh mm ss sss format The seconds can be either an integer or a floating point number REQUIRED dec The J2000 declination in in dd mm ss ss format The seconds can be either an integer or a floating point number The is option REQUIRED epoch the epoch for the proper motion The only allowable value is J2000 0 no leaving epoch false is probably the
41. t as this doesn t use the standard ASCII double quote character It will be helpful if you give the file the extension tls for target list as this is what the program will look for To use the tool do the following 1 If you ve brought the file with you on your laptop sftp it over to baggins A convenient place to put it is the desktop users LMI Desktop but it sure would be nice if you moved the file to the trash at the end of your run Start the tool by double clicking the observerTargetList Tool icon on the desktop Once started the Observer Target List menu will appear at the upper left on the screen Go to File Open Target List Open Target List will open a standard dialog box for selecting the input file The default extension for the input file is tls for target list and all other types are greyed out simply to make it easy to recognize the file among all the other files that might be in a directory The input file has to be a standard ASCII text file but it can have any extension or none at all Binary files will not be read correctly The open file dialog box allows selection of other file extensions via a drop down menu The user can choose All Files from the file type drop down menu and that allows selection of any file in the directory The files other than tls would still be grey but they can be selected and loaded into the app Multiple input files ca
42. tion of the wheel and the C value is the current position Upon startup LOUI doesn t know what the last demanded position was The Good indicates that the detent is in position If either wheel fails to show a valid position De shows and try Check status If that doesn t work click the home button for that filter wheel located to the right Grab the tab that says Facilities Summary at upper left and pull it to somewhere on the desktop This will keep you up to date on where the telescope is pointing Figure 2 lower status of important sub systems like Is the mirror cover open and the focus value bottom most row Note you can actually detach any of the views by grabbing the tab such as the info tab and dragging them to the desktop Returning them can be a bit tricky but you can always go to window Reset perspective at the LOUI menu bar at the top of the screen Figure 1 TY s Custom Personal A Developer I Dashboard M Image 33 Camera Telemetry 4 Facility Summary Focus Move Target Define ROI Color Scale 4 8 P GP INNA S S wt Control 2 User Button Dither Pattern Slew Pattern Pixel Dump Line Profile Angles x D Test 8 Go Passe S Stop Seres Abon Reset Amplifier A 3 Image Dimension Creation Time Exposure Time s 0 1 Subframe H Filename Number of
43. ty of the author And don t forget that in any publications that use LMI please please please include the following in the acknowledgements These results made use of Lowell Observatory s Discovery Channel Telescope Lowell operates the DCT in partnership with Boston University Northern Arizona University the Univer sity of Maryland and the University of Toledo Partial support of the DCT was provided by Discovery Communications LMI was built by Lowell Observatory using funds from the National Science Foundation AST 1005313 Well it can hurt under certain circumstances If an exposure or readout is under way and you kill LOIS there can be funny system lockups or failures in communicating with the CCD controller hardware This might necessitate a reboot of the lemi computer which is not the the end of the world but is a somewhat bigger deal than you d imagine If you have an exposure that just won t abort or you just can t wait for it check with your operator about doing the whole white button procedure But seriously I ve never had this happen and most of the time killing lois and restarting it is perfectly safe 20 A Observer Target List Probably shouting the coordinates over to the telescope operator is not the most efficient way of conveying the information and it has some potential error associated with it Instead there is an astronomer friendly interface that allows one to construct an ob
44. ure length the number of exposures at each point the filter the offsets and whether the move is a slew or a dither e filter If this is not specified it will default to whatever filter is in place at the time the sequence starts e muRA muDEC and epoch the proper motion in mas yr to be applied and the corresponding epoch Note that muRA is really muRA cos DEC this is the form that most catalogs and SIMBAD provide e dRA and dDEC any non sidereal rates that need to be applied for tracking The units are arc seconds per hour e rotator PA By default the rotator PA is set to 0 but there may be occasions where the user would like a non standard orientation e rotator Frame Either Target or Fixed This is a rather obscure parameter and we suggest leaving it at the default e xi and eta Rather than provide RA and DEC it is possible to simply specify tplane offsets from the current position The offsets are in arc seconds and will be performed as an absolute offset See Section 3 6 1 e comment This character string will be to added the header The comment must be enclosed by double quotes e commandOption This determines if the command is a slew or a dither A few things that are worth emphasizing 1 The error recovery is not very robust so it is imperative for the observer not simply start the sequence and walk away Always check on the progress of the pattern at least the first ti
45. y mirror is in position and the primary mirror supports tweaked and stable and that the dome is in position If you re using the guider and the guider is guiding GDR will be green as well The AOS light may occasionally flicker this is just due to the secondary being tweaked to adjust for temperature and elevation changes don t worry about it 3 6 Some Useful Observing Tips 3 6 1 Offsets Directly below the filter wheel display you will ind a TCS Offset Commands This is minimized by default open it by clicking on the chevron There two categories of offsets absolute and relative and three projections that can be used tplane simple or pa Let us explain 12 e Categories Absolute Once set the absolute offset is relative to the current target RA and DEC and hence if you apply a 10 10 offset you will move 10 and 10 Applying it again will not move the telescope because you re already 10 10 away from the target If you were to then enter 20 20 the telescope would move another 10 10 Furthermore whatever you ve applied here will continued to be applied to every new pointing yikes until explicitly cleared Relative This commands allows you to enter an offset of 10 10 Clicking it a second time will move the telescope an additional 10 10 e Projections tplane In tplane coordinates you are basically specifying how m
46. y to have overlooked a step Who Are You Going to Call For things that go significantly wrong at night so that they hamper observing let the telescope operator know and she he will initiate the appropriate phone calls to get you back on the air and happy For questions that can readily wait until the next morning How do I change the size of the measuring radius in imexamine email phil massey lowell edu 8 Acknowledgements and Credit Line LMI was designed by Edward Dunham and built by Ralph Nye Rich Oliver and Steve Lauman The con trol software and user interface for LMI were written by Peter Collins and Saeid Zoonemat Kermani Saeid also provided the Observer Target List application described in Appendix A Funds for the construction of the instrument were obtained from the National Science Foundation through AST 1005313 PI Philip Massey Edward Dunham Jeff Hall Deidre Hunter and David Schleicher all made invaluable contribu tions to the NSF proposal Lowell s Millennium Fund has also provided important support for finishing many of the commissioning tasks The original concept of basing the DCT s imager around a single large chip was due to Bob Millis who also came up with the name This manual is a work in progress and so far has received useful comments from Peter Collins Deidre Hunter Matthew Knight Stephen Levine Larry Wasserman and Saeid Zoonemat Kermani although any errors or omissions remain the responsibili
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