DeVeny Operations Guide
Contents
1. i Starting the control software GoQat and slitviewg The slit viewing camera is operated through USB connections on both the instrument and computer room ends connected by a fiber based extender the extender unit on the telescope has a separate DC power supply The camera is controlled by the computer vishnu through the GoQat software package and operated on sky through the locally developed IDL slitview package To start up the slit viewing camera and software GoQat i From a local terminal window on baggins login to the control computer vishnu ssh X lois vishnu password lois password ii In this terminal type gogat start This script will check for and create a data directory titled with the current UT date and start up GoQat The script is home lois bin gogat start iii In the GoQat GUI Figure 2 Camera menu Connect to CCD camera Camera tab Set H and V binning 2 Set Exposure 1 s Files tab Folder for saving CCD image Select Other i e lois deveny 2015mmdd Autosave each image check Base file name for CCD image enter i e 2015mmdd Save files with number starting from start at 1 and adjust as necessary IDL slitview package i Open a second terminal window to vishnu logging in as in i ii Change directory to the working data directory for the night i e home lois deveny 2015mmdd iii Type idl to launch idl The slitview code automatically compiles iv Attheidl prompt type2. slitviewg This launches the slit viewing camera top level control GUI Figure 3 GoQat File Communications Cameras Filters Focusers Miscellaneous Windows Help Quit Save CCD image Save autoguider image CCD camera autoguider telescope Focus Files Tasks 3 t i Camera status Imaging area Horizontal Vertical Cooling Off CCD temperature 0 0C 3 p Camera status Idle Top right corner H2 V2 752 580 Full frame Get In aging region Bottom left corner H1 V1 1 zi Set H and Binning 2 2 v binning 2 Exposure type TARGET w Filter w Temperature C 5 00 Ignore cooling E Display Notify FITS keywords Telescope Discovery Channel Telescope Instrument DeVeny Spectrograph Observer Object Exposure s 1 Num 1 Start Exposure Cancel E posure Interrupt and Read 2015 04 20 14 52 54 gt Is colour No E 2015 04 20 14 52 54 gt Has shutter No 2015 04 20 14 52 54 gt Can set CCD temperature No 2015 04 20 14 52 54 gt Can pulse guide Yes 2015 04 20 14 52 54 gt Can abort exposure Yes 2015 04 20 14 52 54 gt Can stop exposure Yes 2015 04 20 14 52 54 gt gt gt gt gt Opened CCD camera f E Figure 2 GoQat camera software interface V Running the slitviewg GUI 1 Acquire Image Take an image with integration time ttime The file name
3. and to turn on the dome flat lamps Example count rates for the lamps are shown in Figure 9 Flux in the UV with both lamp sets is very low the low bank lamps can be used with long exposures to avoid saturation using the top end lamps redward of 4000 We are looking into installation of UV emitting lamps in the top end fixtures There is evidence of significant instrumental flexure at large zenith distance when coupled with large rotation angles For this reason observers may elect to take arc line spectra and flat fields 14 near observed sky angles The top ring dome flat lamps may be used for this purpose by rotating the dome in front of the telescope the amount of returned scattered light will be lower than that obtained with the flat field screen Fringing in the CCD with the deep depletion device is significantly reduced from the thinned CCD 42 10 For example Figure 10 shows normalized flatfield profiles extracted from 150g mm top end dome flatfields where approximately 1 3 fringe amplitudes emerge redward of about 8400 A Small amplitude fringes can also be seen redward of 8000 A in Figure 9 s 400g mm flatfield profile In comparison the thinned CCD exhibited 5 fringing at 7000 A rising to 20 at 8000 A and 40 at 9000 A DeVeny Dome Flatfield Count Rates T 200 T T T T T L a Low Bank 300g mm ADU min zl it L a B i J y Top End 400g mm GG495 ADU s amp i 2 N a _
4. deveny terminal type st to check on the status of several processes lois the ntp client and sequester If ntp is not running type timefix If sequester is not running the host deveny will need to be rebooted contact plc szk or tbida lowell edu iii On baggins if there is a DeVeny LOUI in the dock open it and then exit the application from the top level pull down menu Then double click on the DeVeny LOUI in the upper right corner of the left hand screen to start a new copy The DeVeny LOUI is shown in Figure 4 If both lois and temperature logging are running there should be CCD temperature and heater readouts appearing in the log every 5 minutes The temperature logging commands are routine and generated from an external temperature monitor and will not interfere with operations iv If lois is not running type lois amp in the deveny terminal A series of lois startup messages will be printed in both the terminal and the lois console on LOUI v In DeVeny LOUI click on Initialize LOIS in the upper right to enable the camera control storage path and telescope telemetry capabilities in LOIS vi There are several DeVeny specific LOUI features of note 1 In the Image perspective the DeVeny pulldown menu provides several graphical functions with region of interest mouse selection for quick look analysis including Gaussian profile fitting of spectral lines and spatial continuum width and a plot function
5. in the cabinet in the instrument lab on the shelf below the LMI filters Use the grey molded grating case on the table to transport a selected grating to the observing level Take only 1 grating up at a time to leave an open slot for the grating to be removed from the spectrograph a Move the telescope to this position El 45 deg Cass rotation at 90 deg b Move the grating tilt to 10 c Slide back the retention lever and open the access port d Locate the grating cover in the case slide the cover into the slot on the camera side of the cell e The grating cell will be removed with motion down and back hold onto the cell handle with 2 hands at all times Put the removed cell in the open slot in the case f Pick up the grating cell to be installed and slide it into the carriage by lining up the steel guides in the carriage slots Push the cell fully into the carriage to properly seat the holding spring plungers in the detents Give the cell another push left to define it flush against the guide g While restraining the grating cell with a hand on the handle slide out the grating cover and place it in the case Close and lock the case h Close the access hatch and lock it with the lever i Rotate the grating to the desired angle the read scale units are not degrees Some example grating settings are shown in Table III including suggested collimator focus settings A sample arc line spectrum is shown in Figure 8 13
6. to view an average full spectral profile 2 In the DeVeny Control tab the Comparison Lamps widget provides access to arc lamp power controls click Enable for access 3 In the User Button tab the deveny FitsSe button provides fields for entry and storage in image headers of keywords for the grating in use and its tilt the slit width and collimator setting vii At the end of the observing session 1 In the Comparison Lamps widget Enable the lamps Then click All Lamps Off 2 Exit the application with the top level pull down menu See the LMI user manual for more discussion of camera operations and LOUI and IRAF quick look software as DeVeny camera operations are very similar i P Developer if Dashboard pies tet come M eet Te ote faai 105 BON Vet Temp ar fx Camera Telemetry Facility Summary LBF DeVeny v Define ROI Color v Scale lt Q 8 B lt CB AAAA 7 OB DevenyConrol 2 2 User Button Pixel Dump Line Profile 2148x516 09 22 21 02 est Go Stop Series Abort Reset testfits 1199 340 3229 00 2426 27 172 51 Hii Subframe 0 Exposure Time s 10 Rows per Bin 1 s v e 7 value LBF 1 Image Y 1705 1132 Columns per Bin 1 Over Sean 50 Comparison Lamps Enable Disable _Cd lamp Ar lamp 2015 04 30T07 45 10 07 00 SubFrame Definition Light Path 2 Mirror Cover Instrument Cover Fold Mirror TEST templ
7. 2249 temp2 3334 setl 2249 heati 336 3 0 00 Readout is Complete etpoints 109 95 8 00 ctivate 2 3323 sett 2249 heati 336 Observer Larson LO Path home obsdeveny 20150430 File Name 20150430 001 Lfits s 109 95 8 00 ated 25 setl 2249 heat 448 Total 182 04 CB s 109 95 0 00 Used 119 25 CB ctivated Available 62 78 CB TCS AOS DOME Figure 4 DeVeny LOUI The displayed and stored images are oriented with red to the left and blue to the right c Set up of the spectrograph mechanical stages The mechanical adjustments of the slit jaws decker plate filter wheels and grating tilt are located on the left front side of the instrument The collimator focus adjustments are made at the back end of the instrument at the outside radius of the cassegrain rotator When the telescope is parked at the zenith a rotator physical angle of 180 deg will provide good access to the mechanisms Figure 5 shows the layout of the components in this area i Setting the slit width with the micrometer head May 27 2015 notice on the slit micrometer The DeVeny slit jaw adjustment micrometer is out of position through slippage of the barrel by turning while clamped or otherwise loosening of the barrel in the mount The result is that the zero closed point is off and adjusting the slit width is now trickier Here s what to do 1 First make certain that the micrometer clamp ring is unlocked If it isn t unlock it CCW until loos
8. 3 L a ho 4 B E ff l MK X E g L ia el 3 5 100 l r it So F J 7 5 E T j 7 3 kk Top End B0Og mm ADU s E O B 50 7 a m g H L N D J Z hee il L va a 0 ja l 2000 4000 6000 8000 10000 Wavelength A Figure 9 Dome flatfield count rates with select DeVeny gratings Note the difference in scale ADU min for the low bank lamps 15 g mm mazi eld Extraction Top ring lamps 20150507 ee i ji j ja iri yg wiht Fr ormali N al li Mi iil i i Hola 1 Asana A yn 0 Wavelength A Figure 10 Normalized and offset flatfield profiles for the 150g mm grating with no blocking filter purple and with GG495 orange which show the emergence of fringes of approximately 1 amplitude redward of about 8000 8400 c Arc lamp spectra To take arc spectra turn on the desired lamps insert fold mirror C into the beam and CLOSE the instrument cover The underside of the cover is white and is used as a scattering surface for the arc lamps It takes about 6 minutes for all the lamps to stabilize as shown in Figure 11 courtesy N Moskovitz Nominal exposure time for the arcs with the low dispersion gratings is about 20 s when the lamps are warmed up C
9. DU The camera is uncooled so the hot pixel count increases with exposure time The camera is USB based and is run by a linux machine using the GoQat software package and operated for observing by a custom IDL GUI Typical image download times are roughly 0 2 s using USB2 The camera is always operated binned 2x2 to avoid the interline response pattern Specifications Pixel scale 0 253 arcsec binned pixel Image size 376 x 290 16 bit pixels Field of view 95 x 73 arcsec f CCD camera A major component of the DeVeny DCT upgrades is the new CCD camera developed at Lowell and operated with ARC Gen III control electronics The CCD is an e2v CCD42 10 deep depletion device which replaces a standard silicon CCD to reduce fringing in the red end of the spectrum The CCD has 2048 x 512 pixels each 13 5 microns square The device is AR coated with e2v s 4 layer Astro broadband AR coating Specifications Gain 1 52 e ADU in the lab to be verified on the DCT Read noise 4 9 e to be verified on the DCT Linearity tbd Fringing Approx 1 3 amplitudes redward of 8000 9000 A see example in Figure 10 Operating T 110 C Dark current tbd very low though Read out time 8 s Pixel scale 0 34 arcsec pixel 3 Basic Operations Items covered here are spectrograph specific More general observational procedures like setting up target lists and sending targets are well covered in the LMI user manual a Slit viewing camera operation
10. DeVeny Spectrograph Discovery Channel Telescope Reference and Operations Guide v0 2 11 June 2015 T Bida S Levine 1 History Overview The DeVeny spectrograph was built and known at Kitt Peak National Observatory KPNO as the KPNO White Spectrograph and had a long career at the 36 telescope there before being retired Lowell Observatory acquired the spectrograph from KPNO on indefinite loan in 1998 a new CCD camera was built for it and the instrument was further modified for installation on the 72 Perkins telescope in 2005 Following 8 years of service there it was removed in 2013 for upgrades for installation on the DCT instrument cube in February 2015 where it is currently undergoing commissioning on the DCT The spectrograph was designed for f 7 5 telescope optics and new re imaging optics were designed and fabricated to match the spectrograph with DCT s f 6 1 beam The DeVeny DCT Spectrograph system introduces the f ratio matching optics a deep depletion version of the e2v CCD42 10 CCD 2048x515 13 5 micron pixels mounted in a new dewar with a Stirling cycle cooler and a slit viewing acquisition camera Behind the shutter decker and slit jaws there is a pupil matching lens order blocking filters an off axis parabola collimator and a grating carriage that holds one of a set of 128x154mm plane reflection gratings The image is formed on the CCD by the f 1 25 Wynne camera which has two powered reflective surface
11. Table III Example grating settings approximate Grating g mm Grating Tilt Wavelength Range Tilt Scale Collimator Focus center A A 1 tilt unit nominal line width 150 12 0 2500 11300 6870 150 12 6 3200 12000 7600 450 300 13 25 2880 7350 5110 1300 300 13 75 3600 8000 4800 1300 470 400 16 0 4900 8300 6620 967 460 GG495 400 17 5 6280 9700 7360 967 1200 n a 6200 7300 6750 2160 n a n a MET T a4 awi a al an Figure 8 Arc line spectral image 300g mm grating with central wavelength setting of approximately 6000 The 50 columns of pre and postscan are visible The dispersion direction in displayed and stored images is red to blue left to right 4 Taking calibration data and focusing the telescope a Bias frames To take bias frames in the LOUI interface select the Camera Control tab select Frame Type bias set the number of exposures required and click Go The exposure time setting is ignored when Frame Type is bias b Flat field spectra For dome flats insert fold mirror C that feeds the spectrograph into the beam and open the instrument cover There are 2 sets of dome flat lamps the boom lamps that are used for LMI and controlled via the OCS by the telescope operator and the ring lamps that are controlled by a dedicated power supply on the mount Ask the TO to point the telescope at the flat field screen
12. V devenypdu socket assignments Socket 2 Cadmium Cd comparison lamp Argon Ar comparison lamp 18 Socket Neon Ne comparison lamp Mercury Hg comparison lamp Grating tilt motor and Shutter b If the lamps cannot be controlled though the LOUI widget The DeVeny calibration lamps powered through sockets 2 5 on its PDU are to be controlled through the control widget in the DeVeny LOUI The widget has a Enable button which will give the user control of the 4 lamps each button is labeled with the lamp it is controlling It is possible that the socket connection to the PDU can drop out which requires a restart of joe to re establish the connection and thus control of the lamps So if one clicks Enable and the names on the buttons do not update to the lamp names or if there is ever a red ish message in the widget that says that the connection is broken then please restart joe before attempting to log in again and operate the lamps Note that one only needs to restart joe when it is necessary to operate the lamps to avoid affecting other GWAVES operations If the socket connection is lost while any of the lamps are on please regain control immediately in order to turn off the lamps As a next to last resort try logging directly into the PDU devenypdu lowell edu through its native web interface a Open a web browser and point it to http 10 11 13 124 webipc html b Login with IPC login Port 23 S
13. admium Cd lines occur primarily from 3200 to 5500 including 3 lines in the green gap around 5000 Mercury Hg covers roughly 3300 to 5800 neon Ne covers roughly 5800 to 8600 April 2015 Ne is burned out replacement on order and argon Ar covers roughly 6900 to 9700 Appendix A attachments show blue and red side arc line identifications for the 300g mm and 400g mm gratings the line list in IRAF format is included 16 1 1 1 0 0 9 0 8 Normalized peak height 0 7 0 6 aN fi I 1 1 L fi L 1 I L fi f i 1 fi L 1 I 6 8 10 12 14 16 Time since lamps switched on min Figure 11 Arc lamp warm up curves d Focusing the telescope on the slit The telescope is focused on the DeVeny slit by piston of the telescope secondary mirror The most straightforward way to do this is via the slit viewing camera GUI as described in that section above Spatial focus of a dispersed star should be checked following a focus run The DCT M2 focus offset for the DeVeny as is approximately 1050 microns Use a Mag 13 star approx for focusing with ttime 1s 5 Setting up for and taking object spectra Utilize the slit viewing camera to identify and offset targets onto the slit The position angle of the slit on the sky is called the Rotator IPA ask the TO to set this as required Also fill in the value for IPA in the slitviewg GUI in order that telescope offsets sent from there utilize the pr
14. e 2 Close the slit jaws by turning the mic CW holding onto the ratcheting adjuster at the end Turn it CW until the adjuster ratchets and do not overtighten it 3 Note the reading as it lines up with the indicator mark on the stationary barrel The closed position is well inside the nominal zero position 4 Open the slit 0 006 per arcsec to the desired width Verify the slit width by measuring the projected widths of arc lines 5 Do not lock the clamping ring as there is enough friction in the mic to hold the position It is important to check whether it is clamped before making any adjustments The slit jaw micrometer will remain in this state until the instrument is removed for service slated for the downtime of August ii Selecting the decker setting The decker plate undergoing refinishing and is not currently installed 10 a9vwva gsnvo TUM L ATIVANYW NYNL LON OG peenis Figure 5 Adjustment mechanisms for the slit jaws micrometer head front and rear filter wheels and the grating drive speed reducer and motor switch below iii Selecting front and rear filters There are two wheel knobs on the L side of the instrument one that rotates the front pre slit filter wheel and the other the rear post slit order blocking filter wheel The default settings are C and C clear and clear Rotate the knobs to select the filters needed Under most circumstances the front wheel should be in the clear po
15. fsets 7 Point SLIT Constructs the pointing offset to put a star approximately at the slit center position with specified slit IPA A verification image is automatically taken following the offset 8 ABS dXi dEta Sends an absolute telescope offset in arcseconds in TPLANE dXi dEta coordinates RA DEC directions The offset shown is absolute with respect to the original science target position The field values actively accumulate relative offsets applied through the two REL offset buttons An absolute offset of 0 0 should always put the target back in the original position on the camera In order to establish a new origin after a non zero absolute offset ask the TO to absorb the current offsets and set these fields to 0 Any subsequent offset will be a new absolute offset from the new origin 9 REL Offset Xi Eta Sends a relative telescope offset in TPLANE coordinates of the values in the fields These offsets are accumulated in ABS dXi dEta 10 REL Offset TV X Y Sends a relative telescope offset in slitviewing camera X Y coordinates These offsets are also accumulated in ABS dXi dEta This function can be used to dither along the slit as well as make fine adjustments in the object position on the slit See also the discussion in S 6 on open loop vs guided offsets and why open loop offsets are preferred for target set up 11 M2 Focus Loop Execute a focus loop with an imaged star on the slit plane by piston of the secondary mirror M2 u
16. is written to the following field 2 Read File Loads the image file name in the field into the display 3 IPA To display the compass rose in the proper on sky orientation fill in the IPA field with the current slit IPA measured E of N For the offsetting functions to work properly this field must be properly filled 4 MARK Star Fit a 2 D Gaussian function to a selected star in the field of view click button then select star with the cursor and click A 1 D radial plot with the fitted curve is displayed in the upper right window with a contour plot of the selected star and fit parameters displayed in the middle right window This function is also used to mark an object location for offsetting and focusing 5 Repeat Acquire Take Numexp images in sequence with the specified interval in between Images are currently saved so caution is advised when executing long sequences This function can be used to monitor tracking To interrupt the sequence regain focus in the IDL session window and type C followed by recover To avoid buffer overflow crashes of GoQat on the server set the interval between exposures to 5 s or longer 6 Point REF Constructs the pointing offset to put the selected star in a reference position approximately Sarcsec above the center of the slit The current slit IPA must be entered in the top right field A verification image is automatically taken following the offset See note 7 below regarding of
17. nt filters 2 5mag ND Smag ND 7 5mag ND Rear filters GG420 GG495 OG570 c Slit and Decker The maximum slit length without the decker is about 2 5 arcmin With the decker the maximum slit length is 1 9 arcmin The decker plate and second set of slit jaws are being repolished and coated April June 2015 The slit jaws that are installed have somewhat poor surface quality due to a failed coating run The slit width is adjustable using the micrometer Slit adjustment Focal plane plate scale 0 153 mm arcsec or 0 006 inches arcsec on the adjustment micrometer Minimum slit width approx 0 15 arcsec 0 0005 in Maximum slit width gt 40 arcsec Slit position angle adjustable 0 360 deg with the Cass rotator d Calibration lamps The arc calibration lamps are nominally operated through a widget on the DeVeny LOUI that switches a PDU mounted on the instrument Arc lamps Hg Ne Ar Cd Flat lamps provided by the existing DCT boom mounted flat lamp system or the top ring mounted lamps e Slit viewing camera The slit viewing camera is a Lodestar X2 made by Starlight Xpress The detector is a Sony ICX829AL ExView 2 interline CCD with 752 x 580 pixels The pixels are 8 6 x 8 3 microns with embedded vertical antiblooming circuitry The QE peaks at about 77 at 620nm and drops to 45 at 400 and 770nm The read noise is nominally less than 10e and full well is greater than 50 000 e per manufacturers literature Typical gain is 0 4 e A
18. oper rotational geometry The Facility Summary tab will show a summary of the current telescope pointing status It is recommended to place objects near the center of the visible slit in the image display to avoid some rough patches and edges on the left and right sides of the slit jaws Once the target is centered on the slit telescope tracking can be guided through GWAVES operated by the TO S 6 below To take object exposures select Frame Type object enter the exposure time and click Go It is important to note that at this time an image in progress can only be aborted with loss of the image A near future upgrade to the CCD control software will provide the means to stop and read out an exposure in progress 17 6 Guiding In order to guide the telescope while taking DeVeny exposures ask the TO to set up the off axis auto guider once the object is positioned on the slit It is most efficient to make telescope offsets for setup while tracking open loop i e while not guiding as a guided offset can take up to 30s to complete Open loop offsets on the other hand take only a few seconds to complete It is also important not to issue offsets while guiding at a high repetition rate to avoid out of sequence messages to the guider and TCS Rather confirm completion of any guided offset by taking slit viewing camera images before issuing the next offset 7 Data access for local analysis A fast copy daemon controlled by the scrip
19. ord If the USB connection has been re made and is therefore not world writable the device file ID can also be seen in the goqat start terminal when attempting to connect to the camera during the start up procedure ii If the camera is not visible then check that the USB extender and camera have power devenypdu socket 6 The USB extender connection to vishnu can be checked next followed by the LC fiber connections on both ends If power or any of the USB or fiber connections have been disturbed the permissions on the new USB connection will still need to be changed as in 1 d If the IDL widget hangs At the IDL prompt in the terminal that launched the IDL widget type recover Repeat if necessary e If the DeVeny image pixels are uniformly railed at a single value If the DeVeny images appear to be railed to a single high value like 22000 ADU then it is most likely that the analog power supply to the Leach controller has dropped out This can occur for example through RF interference when operating devices on the spectrograph such as the grating tilt drive or switching the arc lamps The solution is to quit restart and reinitialize lois 20
20. rear of the spectrograph The units are 0 001 inch and a reasonable step size is 30 units or 0 030 in Starting from one end of focus take an arc spectrum and measure the width of a line near the center of the spectrum at each position Line widths can be measured directly within the LOUI imaging pane with DeVeny pull down menu gt Arc line FWHM task Due to astigmatism in the camera the line width will go through a minimum before approaching the optimum line width which for example would be approximately 3 4 pixels arcsec slit width for the 300g mm grating with 5800 A central wavelength The focus curve for this case is shown in Figure 7 Once the desired collimator focus is determined tighten the clamp and turn off the arc lamp 1200 g mm DeVeny Anamorphic Magnification T T T T T Line width pixels arcsec A 400 __300 2 l 4000 6000 Central Wavelength A Figure 6 Projected line width vs grating and central wavelength setting 8000 10000 12 Line Center 1014 51 TTT TTTTTTTTT 300 350 400 450 500 Collimator Position Figure 7 Example focus curve of a Cd line taken with the 300 g mm grating The minimum of the interpolated focus curve is shown in red at collimator position of about 391 The position of the collimator to achieve optimum focus is marked with the purple line at about 460 vii To change out gratings The gratings are now located
21. s and a series of weak fused silica refractive correction surfaces The secondary mirror an aluminized rectangular spot on a key surface introduces a substantial central obscuration in the camera Four spectral calibration lamps Hg Ne Cd and Ar are mounted on the spectrograph front plate and are remotely controllable The spectrograph provides low resolution optical spectra at R500 4000 over a wavelength range from 3200 A to 1 micron with a slit length up to 2 arcmin on the DCT The grating complement currently includes several 1 order blazed gratings from 150g mm up to 2160g mm see table below for details other stock rulings are commercially available An upgrade project is planned to motorize the grating tilt slit width and collimator focus stages and configure them to be operable through remote control software The CCD detector is operated by a Gen III ARC controller from a Linux computer The software that interfaces directly with the controller is called LOIS and the user interface software is called LOUI Both LOIS and LOUI were developed at Lowell and are under active maintenance and development 2 Quick reference specifications and operating options a Gratings All the gratings are 128 x 154 mm 1 order blazed plane reflection gratings The Lowell DeVeny grating complement is shown in Table I A preliminary assessment of instrumental efficiency vs grating is shown in Figure 1 Table I DeVeny Gratings mm Bla
22. sing the telescope active optics system AOS Nexp images can be stacked at each of nSteps focus positions separated by Step with central position Center The focus loop can be monitored through the psf fitting output and messages printed to the terminal window and the focus curve data and fit is plotted in the lower right window M2 is left at the end of travel and the predicted postion for minimum focus is printed in the Send M2 Focus field which must be clicked to send the move to the AOS 12 Send M2 Focus Send a focus offset value to the Active Optics System The value is entered in microns Radial Intensity max 14193 Acquire Image ttime 0 5 Read File TARGET_20150608_0006 fit IPA 291 8 MARK Star Repeat Acquire Numexp 10 Interval s 10 Point REF Point SLIT ABS dxi dEta arcsec dXi abs 23 069 dEta abs 19 530 REL Offset Xi Eta dxi 0 deta 0 0 REL Offset TV X7Y ax 0 0 av 0 5 4 7 1 M2 Focus Loop nExp 1 nSteps 5 Step um 50 Center um 1050 Send M2 Focus i Status fi Exit I U Figure 3 IDL slitviewg control GUI b CCD camera operation The DeVeny camera LOIS LOUI operations are very similar to that for LMI At the DCT site baggins is the UI desktop machine i The camera operating software lois is run from the host deveny open a terminal window Login ssh obsdeveny deveny Password On the white board ii On the
23. sition iv Adjusting grating tilt The grating tilt is adjusted using the AC motor and speed reducer assembly on the L side of the instrument by manually toggling the switch located there the switch direction is labeled Longward or Shortward The ratio of the speed reducer can be increased for fine control of the position by pulling out the spring loaded shaft handle and rotating it between positions v Focusing the spectrograph The DeVeny is focused by manual piston of the collimator The recommended focus values in Table II should be tested prior to making adjustments and these values should also be used as a starting point If necessary to adjust and measure focus 1 The optimum line width is a function of the grating used and the central wavelength of the setting through anamorphic magnification of the imaged slit See Figure 6 to determine the projected line width in pixels arcsec slit width 11 2 3 4 5 6 Turn on an appropriate arc lamp s the lamps take several minutes to warm up Bring up a laptop to the observing level so you can VNC into baggins to take arc spectra and measure the line widths Loosen the clamp on the side of the white cylindrical cover at the back end of the spectrograph by turning it CCW a few turns The mirror piston position is adjusted by turning the knob at the end of the white cover There is a three digit mechanical readout showing the position on the right
24. t loiscopy will copy the Deveny spectra files to the directory deveny yyyymmdd on baggins from the corresponding data directory on deveny itself where LOIS writes the original data The naming convention yyyymmdd is the UT date of the night which is set on LOUI via Set Standard Image Path And Observer in the Info Tab The fast copy daemon runs on baggins and is started and stopped with a cron job and will be enabled between 1615 and 0815 MST every night This operation will be updated in the near term future for greater adaptibility For daytime operations the daemon may be enabled manually with loiscopy The daemon status can be checked at any time on baggins with the command loiscopy status There is also a pdf of the loiscopy document Fast Copy Support in the Documents directory on baggins 8 Troubleshooting notes a PDU socket assignments The DeVeny power distribution unit is remotely controlled through the joeClient PDU tab interface and the arc lamp sockets are separately controllable through the DeVeny LOUI widget The telnet socket connection to the PDU is established by the joe process and the PDU telemetry is then displayed in joeClient and for the lamps in the LOUI Comparison Lamps widget if Enabled Socket assignments are shown in Table IV Sockets 2 3 4 and 5 operate the comparison arc lamp power supplies Sockets 1 6 7 and 8 should always be on if the DeVeny is installed on the telescope Table I
25. tacked No One must click Later and Run to get past the Java version popups then click in the Java applet window to update the display If all the buttons show actual socket names then control of the PDU is enabled Please be sure that none of sockets 1 6 7 8 are ever turned off c If the slit viewing camera will not open We recommend that your TO troubleshoot this or call Tom or Stephen If you bring up GoQat and it does not show an available CCD camera then this means that the computer is not connecting to the slit viewing camera The most likely problem is that there has been a break in the USB connection to the camera Check the following i On vishnu type lsusb Look for a return like 19 Bus 001 Device 012 ID 1278 0507 Starlight Xpress Lodestar autoguider If there is no such return then the camera is not visible and go to step ii If it is visible then check that the device file is world read and write accessible ls al dev bus usb 001 012 with 001 012 to be replaced by whatever numbers show up on the response to Isusb Look for a listing like crw rw tw root root 189 11 Apr 14 00 37 dev bus usb 001 012 If the 3 w world writable is missing in the permissions i e crw rw r root root 189 11 Apr 14 00 37 dev bus usb 001 012 then this must be modified with chmod with the following command sudo chmod 0666 dev bus usb 001 012 sudo will then prompt for the lois passw
26. ze Dispersion Free Spectral Comments Wavelength A Range A be g 150 EC a E Ee a a DeVeny Telescope Fold Mirror Efficiency vs Grating is T T T T x T T 0 20 F 400g mm GG495 Fal H 300g mm 4 0 15 ___ 150g mm 0G570 2 150g mm J Efficiency 6000 Wavelength A Figure 1 On sky measured DeVeny efficiency vs grating The vertical line at 6000 A shows where 2 order leakage would begin for unfiltered spectra The spectra were taken with a 5 arcsec wide slit on 20150507 of Feige66 150 and 300g mm and Feige34 400g mm The absorption and emission features are relics of the stellar spectrum not actual efficiency variations b Shutter and filter wheels The iris shutter is made by Uniblitz and was replaced with a new shutter for the DCT installation It is positioned above the slit assembly therefore the slit viewing camera will be blocked from the sky and the images will be blank when the CCD is reading out The photometric accuracy of the new shutter has not yet been measured The order blocking filters are installed in the rear filter wheel These are 1 75in x 2mm thick circular filters fabricated from Schott glasses polished to 1 wave inch with 1 arcmin wedge maximum and broad band AR coated on both sides Both filter wheels are 5 position with an empty position available in each Table II Filter Wheel Positions ND neutral density grade Fro
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