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KPNO MOSAIC-1.1 IMAGER USER MANUAL Version: 4.2

1. EPA V RR Ra de 59 4 8 THE VARIABLE PIXEL SCALE AND ZERO POINT UNIFORMITY senes 60 4 9 STACKING 5 5 61 4 10 SIMPLIFIED SUMMARY OF THE PROCESSING 5 64 5 0 APPENDIX A MISCELLANEOUS SOFTWARE COMMANDS 65 6 0 APPENDIX B DIFFERENTIAL REFRACTION 66 7 0 APPENDIX ISSUES ABOUT 67 8 0 APPENDIX D FLAT FIELD 0 68 9 0 APPENDIX NOCS MENUS AND WINDOWS IN 69 10 APPENDIX EF GOT CHAS 76 11 APPENDIX G 5 1 1 21 78 11 1 THE ADC DOES NOT SEEM TO BE REACTING FAST ENOUGH eeneeene 78 11 2 LOSS HEADER INFORMATION o cesccccccsscsscscssscssesesccsecsscssssesssssssusessssssessesessesssesseass 78 11 3 WHEN DOI NOCS START NOHS 78 11 4 ICAN TSTART THE NOCS SOFTWARE ecce trennt 79 11 5 THE SHUTTER RETURNS TO THE DARK POSITION AFTER EVERY 79 11 6 EXECUTED A SCRIPT BUT NOTHING HAPPENED 80 11 7 IT TAKES TOO LONG FOR THE PRIMARY MIRROR TO SETTLE DURING A MOSDITHER 255
2. ee egeo 24 FIGURE 18 A SCHEMATIC DRAWING OF THE LAYOUT OF THE TV CONTROL PANELS AT THE 0 9 26 FIGURE 19 THE 4 M CORRECTOR OPTICAL LAYOUT FIGURE 20 THE 0 9 CORRECTOR OPTICAL LAYOUT FIGURE 2 1 THE ADE GU nee nete eileen aerae ede Wen eke Chee ee oe vex FIGURE 22 THE MOSAIC DESKTOP ICON TO LAUNCH THE MAIN MOSAIC GUI nennen 32 FIG RE23 THEMAIN MOSAIC GUI cris n rt ette tre o ettet t etu e s Habet i certe 32 FIGURE 24 THE NOCS MOSAIC STATUS ALL WINDOW eee enne nnne nnne reete tese tenentes 33 FIGURE 25 THE MAYALL 2 LEFT HAND MONITOR WITH NECESSARY MOSAIC WINDOWS SHOWN 33 FIGURE 26 THE MAYALL 2 RIGHT HAND MONITOR WITH NECESSARY WINDOWS SHOWN FIGURE 27 THE MAYALL 2 TOP MONITOR WITH NECESSARY WINDOWS 5 nnns FicURE 28 THE NMSL GUI WHERE MOST OF THE EXPOSURE INFORMATION IS DISPLAYED FIGURE 29 THE NGUI PROVIDES THE CREATION OF FIGURE 31 A MOSAIC LEGACY GUI DISPLAYING TEMPERATURES ccccscccsssssessesecscesssssscescesscsesssseeseusssscsscsessusususessses 36 FIGURE 32 A MOSAIC LEGACY GUI ENABLING FILTER CHANGES SETTING OF THE TELESCOPE FOCUS 37 FIGURE 33 THE ADC GUI MINIMIZED csceccsesccscescescesccsscsscescssscccsssesssessusesecsccsessussessesesscssssuseuseuseuscese
3. ready None Dark Guide Restore Camera N Focus 0 82 Camera S Focus 230 ADC 1 Angle 3207 ADC2 Ange 2210 0 Pedestal Focus 8364 00 microns View Messages Apply Update Clear eum Usage hints appear here Figure 32 Mosaic legacy GUI enabling filter changes setting of the telescope focus etc Note It is essential that you select Guide in the ready line above at the beginning of the night 6 ADC control 4 m only the ADC controls GUI IX ADC Co N Figure 33 The ADC GUI minimized To interact with the ADCs one needs to click on the yellow bar 7 A terminal window a window logged in to mosaic1 used for editing and executing scripts 37 N NOCS xterm 2 1 1 4 cd exec observer amp mosaici 4m exec TESTb shi A Figure 34 An xterm window useful for typing in NOCS commands Other Handy Programs Mosa Mosaic Menu Ready Start n 52 4 Figure 35 The Main Mosaic GUI TRUSS TEMP 4 m only A useful program to launch is the Truss Temperature GUI This will display the current 4 meter truss temperature mirror temperature and ambient temperature Normally all 3 temperature display boxes are green but when the truss temperature varies by more than 1 degree since the program was launched or reset it will turn red indica
4. VNC mosaicl 4m 1 monsoon KPNO ameter Autolog Control Panel Image directory daiaZ observer 20101 104 meer rar set to 2011 ile Instrument Mosaict NORO TRAF XIntool Version 1 3EXPORT TENE Process Status Shared Cache Real Tine Display Paths amp Files S Options 7 mosoiet_01901815 RTD i Print log sheets automatically 10 10 88 Marke Tel 9 20 03 D MIlls File KPNO 4m Telescope UT Date Nov 42010 Image filename Object Dee fest obe 01810 2324 10 46 60 57 30 98 20004 101811 Pn8 2324 37 89 60 54 10 80 2000 0 2 10101812 22 22 98 2 SMC Page Usage 14 01 14 01 Disk Usage 17 86 61 00 50 79 2000 Connect Status oso Sheena GE is 23 24 24 22 60 59 11 00 2000 0 23 Fest f stime f 2 370 Pes TER P8 2323 56 74 60 53 50 89 2000 dest focus ni01815 5 s ETE 101802 st focus 154 uith average FUHH of 2 29 2324 19 46 60 57 30 89 2000 0 0 15 do e ep viae Fe eo th average FUHH of 2 88 uith average oF 3 22 7 with average FUHH of 3 45 E with average of 2 79 101802 st focus 9754 with average FUHH of
5. cese 75 AN SATURATED IMAGE os s ete Ee e SERE AMET II DR d e TG egets 77 1 0 Mosaic 1 1 Overview At Least Read This The Mosaic 1 1 imager is a wide field imaging camera built for use at the 4 meter and WIYN 0 9 meter telescopes at Kitt Peak National Observatory KPNO In 2010 the controllers and CCDs for Mosaic 1 1 were upgraded While the basic design of the instrument remains the same 8k x 8k imager with 15 micron pixels the operation and characteristics have changed significantly so please take the time to at least review the current characteristics 1 1 General Characteristics Arrays Eight 2048x4096 e2v CCDs thinned science grade deep depletion silicon with 2 layer AR coating Image Size 8192 x 8192 18 bits plus header overscan 282Mbytes Pixels Size 15 um 0 26 pixel at the 4 m 0 43 pixel at the 0 9 m Read Noise See Table 2 DQE 38 9 350nm 78 400nm 82 500nm 80 650nm 63 9 900nm average for eight CCDs also see Figure 3 Section 2 1 Dark 4 4 e hr average for sixteen outputs current CCD Gaps 1 2 mm 80 pixels in both row and column dimensions Cosmetics Excellent only three bad columns on entire array very good pixel response uniformity and sensitivity Filters 5 75 x 5 75 parfocal 34 filters now available at KPNO http www noao edu kpno mosaic filters filters html Gain Normal and Low Gain modes available See
6. cl msccmd hselect input I rdnoise gain yes The CCDLIST task in the MSCRED package is specialized for the Mosaic data It provides a compact description of the name title pixel type filter amplifier and 57 processing flags By default it lists all the extensions but the extname parameter may be used to select a particular extension Because all extensions should generally be at the same state of reduction it may be desirable to list only the first extension Like most of the CCD reduction tasks you can also select only a certain type of exposure for listing Examples of the two modes are Summary for all exposures cl gt ccdlist fits extname im1 Summary for all object exposures cl gt ccdlist fits extname im1 ccdtype object List of all extensions cl gt ccdlist obj123 4 4 Getting your Mosaic Data Home Mosaic images are 282Mb each With the short readout time it is common to get 300 images per night which amounts to approximately 85Gb of data per night We no longer support writing data to tape CD or DVD Instead we recommend bringing a portable USB hard drive or transferring your data to a laptop At the KPNO 4 meter there are easily accessible USB ports on the left sides of the mayall 2 and mayall 3 monitors to allow you to easily and quickly backup your data Just plug it in and drag and drop to get your data on your hard drive IMPORTANT Make sure the hard drive is formatted for writing to a Mac
7. US VV tw te os ali Hl zls oa wel va Cancel Figure 53 NGUI Tflat configuration window D 72 DFLATS Observation s DFLATS OBSERVATION CONFIGURATION a 1212222 2 Wie 1 22 e 1 1 2x2 4 1 1 22 1 1 4 1 1 Dea bo e 2x2 1 _2 2 10 1 1 2 2 v 2 2 2x2 1x1 v 2 2 1 1 v 2x2 OK Lamp Prompt Cancel Figure 54 NGUI Dflat configuration window EM configuration TEST Observation s TEST OBSERVATION CONFIGURATION Viv Riv tly nally nas ally tly tly 2 osf vs va OK Cancel Figure 55 NGUI Test configuration window OC X OBSERVATION CONFIGURATION mao v s z us ua eT Figure 56 NGUI Dark configuration window 73 NJ ZERO Observation s o e ers ol pi esw lve Figure 57 NGUI Zero configuration window Focus ss Focusg csv ve Rs ty tv Un Figure 58 NGUI Focus configuration window 74 moo NOCS xterm 1 DITSCHD 24d3 nohsznohsDramaMew bs DONE OK SUCCESS TAS
8. a few that are specific to the task of displaying a mosaic of CCD images The mapping of the pixel values to gray levels includes the same automatic or range scaling algorithms as in DISPLAY This is done for each image in the mosaic separately The new parameter zcombine then selects whether to display each image with it s own display range none or to combine the display ranges into a single display range based on the minimum and maximum values the average of the minimum and maximum values average or the median of the minimum and maximum values The independent scaling may be most appropriate for raw data while the minmax scaling is recommended for processed data Another new optional answer here is auto which is the default and will try to use the best option given the status of the data Also there is a new parameter set called mimpars which controls the on the fly processing You can select overscan correction flat field correction both or none 55 MSCDISPLAY offers a special mode of display not previously available If invoked before the readout of the Mosaic array is complete MSCDISPLAY will begin painting the XIMTOOL screen with as much data as are available at that moment When automatic gray level scaling is used it will compute the scaling based on the amount of data present when it starts It will then keep the same scaling for the number of display and sleep cycles given by the niterate parame
9. ecl display image00898 ERROR FXF must specify which FITS extension image00898 ecl display image00898 4 frame to be written into 1 16 1 21 549 5588 22 602 ecl imexamine display frame 1 1 NPIX MEDIAN 5 MIN 25 581 7 581 3 68 25 584 2 585 5 006 573 SHC Pag Connect 390 394 2042 2046 381 385 2033 2037 Mosaicl temperature monitor Bi paee r A Switch OFF email alerts for temperature events H H H FR Ew EL m confid ary Pj xgterm mosaiciIni collector collector _snengr_ xgters KPNO 4metd Autolog Pj Autolog Pd Figure 30 The VNC DHS Window where images are displayed 4 MCCD configuration GUI a graphical representation of the Mosaic light path with temperatures displayed AAA Mosaic 1 1 Configuration Monitor ADC 32 07 212 10 e Shutter ready dark jAmbient 7 10 5 Filter Harris K1 004 s 0 82 2 30 2 2 168 6 4 28 7 Focus 8364 Power 5 35 9 Figure 31 Mosaic legacy GUI displaying temperatures 36 5 Mosaic 1 1 Imager the Mosaic GUI to select filters and change telescope focus X Mosaic 1 1 Imager Fitter U B Am ha hal amp next g r i z 03 Us Ud Shutter se Dark Guide
10. testnics offset 200 300 testnics offset 500 300 testnics offset 600 300 providing all the telescope offsets performed by that dither script At this point you can copy the numbers into your notebook or into a file At present we do not have NOCS control of the guider We have incorporated a pause and acknowledgement for reacquiring a guide star Between dither positions it is necessary for the observing assistant to disable guiding while the telescope offsets The NOCS will wait for you to acknowledge that guiding has been reacquired Once the observing assistant has re enabled guiding click the enter key in the xterm window where the script was executed There is also no sound alert yet when the telescope has moved to a new dither position so the user needs to be watchful of this to alert the observing assistant as to the new move These shortcomings in the dither procedure are a work in progress MOSgrid The MOSgrid script provides the ability to image over a grid on the sky while at each point in the grid performing any of the dither patterns just discussed Figure 42 shows an example MOSgrid which used an RAxDec grid and the basic FillGap dither The script performed a 2 x 2 grid and at each grid position the quincunx pattern of the FillGap dither can be seen The dithers used by MOSgrid are exactly those of MOSdither In fact when you look at the MOSgrid GUI see Figure 50 you will see that it simply repeats the dither
11. At the WIYN 0 9 meter emerald has USB access in the computer room Other possible methods of getting your data are via FTP or the NOAO archive Remember you will likely have large amounts of data and the FTP transfer will take a significant time to complete All Mosaic data is archived in the NOAO Science Archive Information on retrieving your Mosaic data can be found at http portal nvo noao edu documentation query noaoquery html 4 5 The Reduction of Mosaic Images The reduction of Mosaic camera images at first glance is just like that of any other CCD camera ignoring the immense amount of data contained in a single Mosaic image As is standard for other cameras reduction requires overscan correction followed by zero and flat field corrections In detail however full reduction of Mosaic data requires a number of steps not normally encountered in the routine reduction of other CCD camera images The driving factor in Mosaic reduction is the expectation that the observer will not simply obtain a single Mosaic exposure of an astronomical field but may want to construct a deep integration from several Mosaic images spatially offset or dithered from each other to cover both the gaps between the individual CCDs and any defects Stacking dithered Mosaic images 58 places high demands on the uniformity of the initial data reduction as well as requiring several additional steps once the basic reduction of the individual exposures is complete
12. Correctors The 4 m corrector is a 4 element fused silica for maximum U band efficiency design with additional internal prisms that serve as an atmospheric dispersion corrector ADC See Figure 19 for the optical layout and refer to Jacoby et al 1998 SPIE 3355 721 for a detailed description of the corrector and ADC Figure 19 The 4 m corrector optical layout All elements are made from fused silica except for the ADC components which are made from LLF6 UBK7 LLF6 and UBK7 as viewed from left to right At the right are the science filter Dewar window and CCD from left to right The ADC elements appear in the middle as four planar elements although they are wedged 26 The 0 9 m corrector is a simple 2 element fused silica design There is no ADC at the 0 9 m See Figure 20 for the optical layout Figure 20 The 0 9 m corrector optical layout Both elements are made from fused silica At the right are the science filter Dewar window and CCD from left to right Coatings and Scattered Light All optics have been coated with very broad band multi layer anti reflection coatings to improve photon collection efficiency and to reduce scattered light Surface losses are 10 from below 3500A to longward of 9500 at the 4 m and better at the 0 9 m In addition all interior structural surfaces have been blackened to minimize scattered light Tests at the telescope indicate that the new correctors suffer significantly less than
13. Figure 15 The blue Wolf Rayet filters for CIII He II and a continuum at 4750 23 DDO 51 5300 Transmssion 4900 5000 5100 5200 5300 5400 5500 Wavelength Figure 16 on band off band filters plus DDO 51 Y band Science Filter TY Filter TV Filter Figure 17 The V band filter installed in the filter track The 2 TV guider filters are visible to the lower left and upper right of the science filter 24 2 7 Operation of the Guider TVs Guiding with the Mosaic is accomplished using one of two TV cameras on the north and south sides of the science field These are intensified fiber optically coupled CCD cameras ICCDs so they can be damaged if exposed to bright light The video signal from the selected TV camera is fed to the guider system The field of view of each camera is about 2 2 arcmin on a side at the 4 m and about 5 arcmin on a side at the 0 9 m The field of view of the TVs is fixed with respect to the science field At the 4 m the fields are approximately 1440 arcsec north and south of the center of the science field At the 0 9 m the fields are approximately 2400 arcsec north and south of the center of the science field TV focus can be moved remotely offsets are 0 9 and 1 7 at the 4 m and 0 1 and 1 9 at the 0 9 m for the north and south TVs respectively At a given location suitable guide stars are almost always available witho
14. Frank Valdes Mosaic Data Reduction System 53 http irafnoao edu projects ccdmosaic Reductions and Guide to the NOAO Mosaic Data Handling System http www noao edu noao meetings spie98 mdhs ps We encourage Mosaic users to read through these documents before attempting to reduce their data The guides also provide a thorough description of all MSCRED tasks that may be valuable during the night s observing The NOAO Mosaic data format produced by the Data Capture Agent DCA is a multi extension FITS MEF file The file contains nine FITS header and data units HDU The first HDU called the primary or global header unit contains only header information which is common to all the CCD images The remaining eight HDUs called extensions contain the images from the eight CCDs The fact that the image data are stored as FITS format images is not particularly significant A single FITS format image file may be treated in the same way as any other IRAF image format The significant feature is the multi image nature of the data format This means that commands that operate on images must have the image or images within the file specified Only commands specifically intended to operate on MEF files such as those in the MSCRED package can be used by simply specifying the file name Commands that operate on files rather than images such as copying a file may be used files In general it is safest to use only MSCRED commands on
15. See Buell Jannuzi s Draft Guide to NOAO Deep Wide Field Survey MOSIAC Reductions http www noao edu noao noaodeep ReductionOpt frames html for more information on Mosaic data reductions The Mosaic camera also has a spatially variable pixel scale that has important implications for ensuring a uniform photometric zeropoint in the reduced images 4 6 Calibration Data to Obtain at the Telescope Good data reduction begins with obtaining good calibration data at the telescope Dark frames may be required but usually not It is safe practice to obtain darks with exposures similar to your science images Dome flats provide basic flattening of the frames to 196 or so but night sky flats or illumination corrections likely are required to produce images that can be stacked without introducing obvious artifacts Using night sky flats we can flatten images to 0 196 Twilight flats do not appear to work quite as well as dark sky flats due to regions of variable thinning that cause slightly wavelength dependent features but they work better than dome flats The default Mosaic dither pattern is a sequence of five exposures designed to ensure at least 8096 coverage for all portions of an astronomical image given the gaps between the CCDs Finally good astrometry is required to register and stack the Mosaic images We have derived solutions for most filters but the scale varies slightly with color so you may want to image an astrometric field if yo
16. Shared Cache Real Tine Display Paths Files Options DetNane nosaicl 560 75 nosaicl 543 92 nosaicl A mosaicl 546 06 859 74 nosaicl 278 00 637 81 nosaicl 150 00 311 00 nosaicl 310 00 612 81 nosaicl 399 10 727 43 SHC Page Usage nosaicldhs 01 nosaicldhs 01 Disk Usage 53 Exp Status Connect Status Figure 48 DHS Real Time Display window File Options msl Connect To Disconnect From rns peu Reset GPX Commands nns nmsli Reset GWC Commands bul nmol nmi Enable Temperature Control nasli 7 Enable ADC Control mst ms Lt nnsli Hide Text Window T rmslGwcHandleValue RECV mse arint adcready immslGwcHandleValue RECV mse thermocouple templ 106 699997 mmslGwcHandleValue URGENT CCD Focal Plate Temperature too LOW 106 700 mnslOwcHandleValue lt RECV gt mse thermocouple templ 106 400002 rmslGwcHandleValue URGENT CCD Focal Plate Temperature too LOW Temp 106 40C inmslOwcHandleValue lt RECV gt mse thermocouple templ 106 699997 mmelOwcHandleValue lt URGENT gt CCD Focal Plate Temperature too LOW Temp 106 700 Sat Oct 23 11 20 04 PM MST 2010 22220200000 Amy Temperature 106 70 Am gwc kpno noao edu 2347 Finished script home observer exec DARK30min sh NMSL Mosaic 1 1 ocal Plate Temperature too LOW Temp 106 rn
17. Table 2 Linearity Good to 0 596 from the bias level up to saturation See Table 2 Table 1 General Mosaic 1 1 Characteristics Observing Normal Normal Low Gain Low Gain Mode No Binning 2x2Binning No Binning 2 x 2 Binning Readout Time 22 seconds 11 seconds 38 seconds 17 seconds including Overhead Gain 1 2 e ADU 0 47 e ADU Read Noise 5 9 e 3 2 e Saturation 218 CCD 312 124 ADC 124Ke ADC full well limit limit limit Image Size 8592x8192 pix 4496x4096 pix 8592x8192 pix 4496x4096 pix with 50 pixel 282Mbytes 74 Mbytes 282Mbytes 74 Mbytes overscan Table 2 Observing Modes and Mode Specific Characteristics 1 2 KPNO Mayall 4 Meter Parameters Count Rates approx for now At UBVRI 20th Mag 0 43 B 376 340 R 390 1 262 e sec FOV 36 X 36 XIMTOOL display orientation North left East down Scale 0 26 pixel at center decreases quadratically by 6 5 out to corners Image Quality The flatness of the focal plane appears to be very good The PSF variations across the entire field of view have a 1 sigma value center to corner of about 0 1 pixels FWHM The star images are nice and round everywhere in the field Artifacts Bad column in section 5 861 864 CCD8 1022 1023 Typical Focus 8700 at 18C etc liquid U filter is 300 units different ADC Atmospheric Dispersion Correction For broad ban
18. and Data Overview The Kitt Peak CCD Mosaic 1 1 camera is a wide field imager having 8192 x 8192 pixels At the KPNO 4 m the pixels are 0 26 on the sky this provides a field of view of 36 arcmin on a side At the 0 9 m where the pixels are 0 43 on the sky the field of view is 59 arcmin on a side Each unbinned exposure with the Mosaic 1 1 camera requires 22 seconds of total readout time including exposure preparation time and CCD readout when in the default 1X1 normal gain mode When used with 2X2 binning the readout time for Mosaic 1 1 is 8 seconds The CCDs are read out through 16 amplifiers by the MONSOON Orange controller The data are placed on a disk drive on the computer named Mosaic1 while users will generally run the entire system from the Mac mini mayall 2 at the 4 m or Linux computer emerald at the 0 9 m in the control room Users can run IRAF and ds9 and perform full data manipulations and reductions on mayall 2 4 m or emerald 0 9 m in the control both of which have the data directory cross mounted Images are 282 Mbytes each and a typical night of 4300 images will produce about 85 Gbytes Be aware that ftping this amount of data to your home computer may take many hours and is likely to time out fail or be killed by the next observer if done on your last morning We highly recommend bringing a large USB drive to plug into one of the Mac minis and perform nightly data transfers The Mosaic 1 1 data are all
19. archived and users may also obtain their data from the NOAO archive Data are written in a Multi Extension Fits Format MEF There are 16 extensions one for each CCD amplifier and one global header the 0 extension see Figure 1 If you want to work with or display only one of the 16 extensions commands such as display image fits 3 and imcopy image fits 14 ext14 fits would work Once the 16 extensions are combined by merging the amplifiers only eight extensions exist and are equal to the CCD number itself DTAAOZ CCD2 2 i EAST Figure 1 The display orientation of the 16 sections of the Mosaic 1 1 imager on the Mayall 4 m The 8 CCDs are divided up into 16 extensions that are labeled in the figure as the numbers 5 The Mosaic cameras require large 5 75 inch filters We can provide an adapter for 4 inch filters but using them makes poor use of the Mosaic wide field of view 1 7 Supplemental Information Other manuals and Web pages to look at Other useful information regarding the use of the Mosaics CCDs and observing and reduction software can be found at the NOAO Mosaic Camera web pages http www noao edu noao mosaic Information of what calibration images are needed can be found in Direct Imaging Manual http www noao edu kpno manuals dim dim html NOAO KPNO Mosaic Web Page http www noao edu kpno mosaic mosaic html WIYN 0 9 m User s Manual http www noao edu 0 9m manual html Buell
20. beginning of the name Use your text editor of choice to edit the file Scripts are text files but are not simple therefore it s not advisable to make a script outside of the NGUI script configuration GUI A simple script looks like this observer mosaic1 4m exec more DflatV sh bin sh FileName home observer exec DflatV sh Object DflatV Script DflatV NumObs 2 Filter 3 V 1003 MONSOON intTime 45 MONSOON row bin 1 MONSOON col bin 1 send project parameters to the KTM nocs set project read common function s and set trap MOSAIC_SBIN nocs functions sh trap trapSignal home observer exec DflatV sh LINENO SIGINT SIGTERM 41 Starting script home observer exec DflatV sh ditscmd nmsl nmsl init ditscmd nmsl nmsl wgui Argument1 Starting script home observer exec DflatV sh checkReturnValue nmsl nmsl wgui Starting script home observer exec DflatV sh set intTime ditscmd nmsl nmsl init ditscmd nmsl nmsl gpxSetAVP Argument1 intTime 45 checkReturnValue nmsl nmsl gpxSetAVP intTime 45 set row bin ditscmd nmsl nmsl init ditscmd nmsl nmsl gpxSetAVP Argument1 rowBin 1 checkReturnValue nmsl nmsl gpxSetAVP rowBinz1 set col bin ditscmd nmsl nmsl init ditscmd nmsl nmsl gpxSetAVP Argument1 colBin 1 checkReturnValue nmsl nmsl gpxSetAVP colBinz1 set expVector ditscmd nmsl nmsl init ditscmd nmsl nmsl gpxSetAVP Argume
21. from an internal reflection off the front surface of the rear element of the corrector despite the use of an extremely good anti reflection AR coating Our investigation suggests that similar 4 element correctors currently in use should exhibit a similar effect and tests performed by Alistair Walker with the CTIO 4 m confirm this analysis Although the ghost pupil can subjectively appear severe when viewed at high contrast for narrow band filters photometric accuracy is preserved when this additive term is removed during the reductions One can avoid the affected region on the Mosaic array by moving the telescope slightly if there is any concern about the reduction process For a description of how to correct for pupil ghost images in your observations you can read the discussion in the NOAO Deep Wide Field Survey MOSAIC Reduction Cookbook http www noao edu noao noaodeep ReductionOpt frames html 2 9 Atmospheric Dispersion Corrector at the 4 m only The Earth s atmosphere disperses the light from stars significantly when observing away from zenith The effect is greatest and similar at U and B where the stellar image is stretched for example 0 5 at a zenith distance of 452 1 4 airmasses and 0 9 at 602 2 airmasses The ADC prisms can be configured via a rotation to counter this effect nearly completely thereby greatly reducing the elongation of the image introduced by the atmosphere Modes of Operations There are three mo
22. not be flat further scattered light from nearby objects may affect the sky over large areas Unfortunately the pattern of scattered light varies as the telescope is dithered A further complication is that computation of an average mode for an image may be affected by scattered light that affects only a small portion of the Mosaic field At this time we are still working on a solution for stacking images of this type The solution is likely to require fitting and subtracting a sky surface to the individual Mosaic images prior to feeding them to MSCSTACK When conditions are favorable however we have produced beautifully flat stacked images free from defects showing the full scientific potential of Mosaic camera and providing a suitable reward for our hard work 63 4 10 ASimplified Summary of the Processing Steps NOTE this section remains relevant for Mosaic 1 1 but is not up to date The next version will have updated information George Jacoby contributes the following sequence It represents as simple a sequence as makes sense for dithered Mosaic images taken under good conditions I CCDPROC to correct for cross talk trim overscan bias subtraction and flat fielding IL MSCZERO apply a uniform astrometric zeropoint to all images of all colors in a sequence dithered or not Identify a star in each frame and set its zeropoint to be identical III MSCZERO using the w key identify 10 20 stars per CCD in one of the frames
23. of all NOCS processes nocs start stop all starts or stops the NOCS observing program nocs ping rack pings the NOCS rack to see if it s alive nocs status disk shows the disk usage nocs set project after the program ID has been set in the NGUI this updates the headers nocs start stop nics opens or closes the instrument control window filterwheel etc Nocs start stop ntcs opens or closes the telescope control system interface nocs start stop ngui opens or closes the NGUI window nocs start stop mccd opens or closes the MCCD and ADC windows nocsMode logain sets the gain to logain mode nocsMode normal sets the gain to normal gain mode nmslReset reinitializes the NMSL by doing the following a resets the systran fibre link b resets MONSOON c loads all default files in order to bring MONSOON to a known state d sets the operating mode normal or logain and enables the sequencer e applies voltages to the arrays after checking the system state is OK 65 6 0 APPENDIX B Differential Refraction With the wide field of the Mosaic imager one should be aware of the special conditions imposed by differential atmospheric refraction during exposures Gary Bernstein motivated this section Differential Refraction Arcsec 1 0 12 1 4 1 6 18 20 22 24 26 28 3 0 Amass Figure 43 A plot showing the differential prismatic distortion due to atmospheric refraction over the extent of the Mosaic field The differe
24. r X r SDSS X ignore X ignore X k1018 nguiShowFilter 10 X i X i SDSS X ignore X ignore X kl019 nguiShowFilter 11 X z 2 SDSS ignore X ignore X k1020 nguishowFilter 12 X 03 X VR Bernstein X ignore X ignore X k1040 nguiShowFilter 13 X Us X Us solid U k1044 X ignore X ignore nguishowFilter 14 X Ud X Ud Dey k1045 X ignore X ignore X Brownian Motion Filter Commands TwilightFlat Object MosGrid Test Refresh Filter s Set Project NGUI v20101011 C 2010 AURA Inc Contact Philip Daly pnd noao edu Figure 38 The NGUI with buttons at the bottom for script configuration Telescope Commands Clicking on any of the buttons at the bottom of the GUI launches a script configuration window with options specific to that type of exposure For instance clicking on the Zero button launches the Zero Script Configuration for writing a script to take biases Figure 39 You can edit the Object Name Script Name Number of Observations NumObs and binning factor Note the Integration Time intTime is set to zero See Appendix E for a complete listing of all of the script configuration windows ZERO configuration SCRIPT CONFIGURATION Object Name ZERO Observations Script Name zlo OBSERVATION CONFIGURATION NumObs 1 Fiter ujv Bl viv R V 4 16 v giv 2 Us MONSOON CONFIGURATION intTime sec
25. scripting setup and adds in the grid type Three grid types are available Random RAxDec and From File These grid patterns work as described in the dither section 51 3 6 Shutting things down and restarting Sometimes things go awry and you need to restart the NOCS software To do so click on the Stop button on the main Mosaic GUI This should close all of the NOCS windows Wait until you see Ready in the Main Mosaic GUI before restarting the NOCS software At the end of the night there is no need to shutdown the NOCS software Please leave it running Also put the shutter into the dark position on the MCCD GUI at the end of every night 52 4 0 Evaluating Recording and Reducing Mosaic Images NOTE this section remains relevant for Mosaic 1 1 but is not up to date The next version will have updated information In this section we discuss the software and observing procedures needed for the following 1 How to evaluate the observations as they are obtained at the telescope including how to display Mosaic images how to evaluate the telescope focus and edit and examine the image headers We also discuss how to log the observations 2 How to read and write the data from to tape 3 Calibration observations that should be obtained at the telescope 4 How to reduce the images Observers familiar with CCD cameras and the IRAF reduction and analysis software will find the processing of Mosaic images to be simi
26. the default of start up mode of operation is for the system to prompt the observer to confirm the ADC mode before starting the first observation with a new filter 29 The 3 ADC modes in detail 1 Null Mode The ADC prisms are set to a fixed position that makes no correction for the atmosphere 2 Track Mode The positions of the ADC prisms are automatically updated at a periodic rate typically 60 second intervals to account for the changing zenith and azimuth directions of the telescope as it moves e g as it tracks during an observation or slews to a new position 3 Preset Mode The positions of the ADC prisms are set to a pre determined location as demanded by the mid point of the exposure In this mode movement of the ADC prisms is synchronized with the data acquisition sequence In this mode the ADC prisms do not move during the exposure 30 3 0 SOFTWARE The software used to operate Mosaic 1 1 is called the NOAO Observation Control System NOCS NOCS is a script based software package meaning all of the data taking will be done through a script that has been created most likely by the observer A script editor is a part of the software package making it simple to create scripts as you observe 3 1 Mosaic 1 1 computers Several computers work together to obtain Mosaic 1 1 data Although the observer should only need to access the computers 1 mayall 2 at the 4 m or emerald a
27. the e2v CCDs gt 200 000 e The logain mode is optimized for low noise performance at the expense of read time and dynamic range The following tables show the performance characteristics of the CCDs in the different observing modes CCD CCD FITS Gain Read Noise Saturation HCTE Dark Signal Amplifier Extension 0 e Level e pix hr 1 Left 1 1 11 5 69 226800 99 9985 3 54 Right 9 1 12 5 93 221400 99 9984 1 76 2 Left 2 1 10 5 43 218400 99 9984 6 78 Right 10 1 13 5 71 217300 99 9986 4 88 3 Left 3 1 10 5 71 218400 99 9984 6 18 Right 11 1 08 5 39 224700 99 9985 6 52 4 Left 4 1 14 5 81 218400 99 9985 4 38 Right 12 1 15 5 65 217300 99 9986 6 98 5 Left 13 1 11 5 77 215250 99 9986 4 26 Right 5 1 11 5 54 217900 99 9987 4 60 6 Left 14 1 14 5 55 215250 99 9988 3 10 Right 6 1 16 5 94 215250 99 9988 3 24 7 Left 15 1 16 5 69 218400 99 9985 2 91 Right 7 1 17 5 75 219350 99 9984 4 00 8 Left 16 1 12 5 99 211150 99 9986 3 54 Right 8 1 06 5 47 216300 99 9986 3 53 Table 5 Normal mode CCD operating characteristics 14 CCD FITS Gain Read Noise Saturation Amplifier Extension e ADU e Level e 123208 99 9985 125829 99 9984 120586 99 9984 120586 99 9986 120586 99 9984 123208 99 9985 123208 99 9985 128451 99 9986 123208 99 9986 123208 99 9987 123208 99 9988 128451 99 9988 123208 99 9985 128451 99 9984 128451 99 9986 115343 99 9986 Table 6 Logain mode CCD oper
28. time so be prepared to gather substantial MBs of data We recommend you bring a large capacity external USB drive or a laptop with a big disk if you are planning to take your data home with you We also offer a logain mode 0 5 e ADU with a read noise of 3 5 electrons and read time of 34 seconds Binning of 1X1 and 2X2 are available as well 2X2 has a shorter readout time near eight seconds in normal gain mode and 14 seconds in logain mode The big difference you will be faced with is the new software The new CCDs and controller MONSOON are run from new software not the old ARCON system The new system to run Mosaic 1 1 is the NOCS NOAO Observation Control Software If you have used NEWFIRM this is the same system adapted for Mosaic 1 1 The NOCS is a script driven system all image taking even a simple test exposure requires a script Some other smaller differences are that there appears to be a lower level of fringing in I or z band Also U band images show a low level 1 2 background pattern that we believe may be related to the thinning process or the anti reflection coating of the CCDs Flat fielding removes the pattern well For the record the read noise in normal gain mode is about the same as with the previous Mosaic system 5 e the plate scale and field of view are essentially the same and the QE has not changed dramatically albeit better in the U and B bands Oh and the same filters are available 1 6 Instrument
29. wgui Finished script home observer exec DflatV sh tput bel end home observer exec DflatV sh Default Mosaic scripts Several default Mosaic scripts are available in the home observer exec directory These are all labeled with a preceding lower case m e g mBias sh mBias sh a single bias exposure mBias 9 sh 9 bias exposures mTESTR sh a single test image in R assuming position 4 at 10 seconds mDark50s sh a single dark frame with 60 second exposure time Stringing scripts together to make a super script You may find it useful to string several scripts together to make observing more efficient To do so simply create a new file that contains each script on a separate line For instance if you want to string five dither sequences together one for each filter to execute the five individual scripts in sequence your file may look like this observer mosaic1 4m exec more standard sh DitherSA92Us sh DitherSA92B sh DitherSA92V sh DitherSA92R sh DitherSA92I sh Make sure this file is executable You can check this by typing 15 l in the home observer exec directory You should see something like this rwxrw r x 1 observer users 11151 Nov 5 04 57 mBias 9 sh rwxrw r x 1 observer users 2545 Nov 5 04 56 mBias sh rwxrw r x 1 observer users 2584 Nov 5 04 59 mDARK60s sh rwxrw r x 1 observer users 13439 Nov 2 14 27 MOSDITHER sh rwxrw r x 1 observer users 2726 Nov 5 04 58 mTESTR sh rwxrw r x 1 obse
30. 11 5 The shutter returns to the dark position after every exposure There are 2 similar lines on the MCCD GUI see Figure 32 associated with the shutter One is labeled shutter the second is labeled ready The top line is actually controls the shutter you can open or close the shutter or put it in the dark position from this line The second line indicates the state of the shutter after an exposure The shutter should return to the dark position after any calibration image a dark bias or dome flat For any sky observations the shutter should return to the guide position instead of dark If it doesn t you may need to click on the guide button for the shutter ready line the second shutter line of the MCCD GUI see Figure 32 After selecting this once it should always return the shutter to the guide position you may need to reselect this after a software restart Remember to put the shutter into the dark position at the end of the night from the top shutter line 79 11 6 I executed a script but nothing happened It could be that the system is simply waiting for the instrument to complete some movement the ADCs may be updating the filter track may be moving to the correct filter position or the system may be waiting on input from you Also check the xterm window from which you executed your script there may be either a Failure or Error message indicating what the problem is If the filter failed to move to
31. 22 4 Q View Window Help NMSL Mosaic 1 1 Thu Nov 04 09 45 19 PM NST 2010 Integration timer 414 0 7 900 0 Am gwcKkpno noao edu 2347 OBJECT Observation 1 1 script OStest sh New Integration Time 5 Ghange integration Tine EE PE X 080 ES Sho 809 804 605 EXE 010 150 210 19 lt 363 0 413 0 303 0 419 0 Gain e fADU Read Noise e 5 0 Truss Temps Read Out s Individual Display zconbi ne ERIGI k 70782 0 95590 4 70788 0 93580 4 69536 0 33672 0 53558 0 95672 0 Weather S NUES NUI CIO i CE SM element DES 14 7902810 80988 0 73023 0 doro ngniTraceSeq cred pud incuiTraceSeq 5 pace ae 2 Options nguiTraceSeq 5 elenenteDBs C 5 VAL dhs tHetallta dhs tHetallata 393 nguiTraceseq INFO gt nguiTraceseq lt IIEO gt nguiTraceSeq lt INEO gt nguiTraceseg INFO gt nane nguiLccals OBS cp 5 T0 VAL op v N 10 x 0 12 AL lt INFO gt opened file hone cbs rver erec 03test sh nguiSetbs lt OBJECT gt Writing observation 1 1 1 1 with DP0S ignoce MPOS ignore TYPE 0BJECT nguiSetExecGlose INEO wrote script fhone observer exec O3test sh Telescope Commands W Filter Commands Focus TwilightFlat Object Refresh Filter s SetPr
32. 300 arcseconds and pick three steps in RA and four steps in Dec your grid would look like the figure below and be repeated two times Each X position will be 300 arcseconds apart For even steps the dither sequence averages the positions about the center of the field For odd numbers of steps one grid point will lie at the center RA lt gt XXX X X X DEC up and down XXX XXX From File This option provides the user with the ability to perform a custom dither The script asks for a filename the file needs to be placed in the home directory and will offset the telescope in RA and Dec to each position specified in the file The file has the simple ASCII format of one absolute offset per line in arcsec as shown in the above 50 examples The script produces an offset that is an exposure for each line in the file Once ended the script returns the telescope to the starting position Some General and Highly Useful Bits of Information All offsets those in the fixed dither pattern scripts and those in the calculated dither scripts are stored in the script only The telescope offsets are written into the FITS header for each offset but no file of the offsets is produced If you wish to keep the dither values you can retrieve them from the script as follows If you have a dither script named mydither dat and you want to get the set of offsets used in that dither typing grep offset mydither dat will produce a listing such as
33. 34 3860 1034 DDO 51 BK 7 85 1 5132 161 5132 161 WR CIII BK 7 68 4 4653 52 4660 50 WR Hell BK 7 73 3 4690 51 4695 49 WR 475 7 78 8 4750 51 4755 49 Table 8 Some of the currently available filters and approximate count rates sec for a 20 mag star See Figures 12 through 16 for plots of the current filter transmission curves ASCII Tables that describe the transmissions are available on the Mosaic Web Pages The U band 0504 filter is based on the same formulation as our 4 filter set liquid CuSO 06 1 Because containment of the liquid requires a thickness around the edge that exceeds the nominal Mosaic dead zone some vignetting is present At the 4 m the vignetting introduces a 2096 loss of light at the edge but recovers to zero loss at 200 pixels from the edge 21 Transmission 3000 4000 5000 6000 7000 8000 9000 10000 Waveength Figure 12 The broad band filter set including the White filter Transmission 10 3000 4000 5000 6000 7000 8000 9000 10000 Wavelength A Figure 13 The SDSS 9 and z filters along with Washington C and M M is the smooth curve slightly redder than 22 p wee Transmission 8 E B B anne Wavelength Figure 14 The current set of Ha plus redshifted filters Note that 16 serves as S11 filter Transmission 4550 4600 4850 4700 4750 4800 4850 Wavelength
34. 4 10 Jpn test MIC son masaict Tai collector collector Figure 26 The Mayall 2 right hand monitor with necessary windows shown the DHS VNC window and autolog And the top monitor should look similar to this mayall 2 in 4M VDU 4meter acorn 4 meter VDU 4 56 05 11 05 2010 LST 0 26 59 900 0 00 Shutter ready quide 23 24 10 47 60 57 31 0 2000 0 5a HA 1 02 16 ZD 30 79AM 1 164 itor VR Bemstein k1040 om OFFSET 0 0 0 0 1 90 s 0 00 0 0 pewar 345 FOCUS 9217 OME 342 5 z d PARAL 1 4 INST MOSAIC FIELD CCD FILTER 12 ADCI 0 NTV 1 10 ADC2 0 STV 1 90 Camera S Focus 150 r ADC1 Angie 000 ADC2 Angle Pedestal Focus 321700 microns wena Figure 27 The Mayall 2 top monitor with necessary windows shown the VDU MCCD GUI Truss Temp 34 The main windows required to observe with Mosaic 1 1 are there are 7 of them 1 NMSL Mosaic 1 1 the main instrument status window with countdown clock detector information gain selection and exposure control pause abort etc X NMSL Mosaic 1 1 Thu Nov 04 07 09 47 PM MST 2010 Integration timer 6 0 8 0 4m gwc kpno noao edu 2347 naam NOCS Status FOCUS Observatio
35. Binning 1 1 2 2 OK Cancel 1 S77 Figure 39 The ZERO script configuration GUI used to create scripts for taking biases To save a script simply click OK at the bottom of the window If a script with that name already exists you will be asked whether or not you would like to overwrite the previous script All scripts are saved in the exec directory home observer exec Note that the shortest integration time allowed is 0 2 seconds and the longest exposure time allowed is 3600 seconds 40 Good script writing It s a good idea to name your script something logical to you and something not too long You will need to call that script by tying the name so keep it simple It s also a good idea to enter the Object Name as something meaningful to you and that observation What you enter here is the Title keyword in the header Executing a script To execute a script make sure you are in the home observer exec directory where all of the scripts are saved by default and type the name of the script preceded by To execute a script called ZERO sh type ZERO sh If you have trouble executing that script be sure that you are in the correct directory a script exists with that name the script is an executable file Editing a script Any script can be edited e g to change the exposure time or filter except the default Mosaic scripts those denoted by a lower case m at the
36. E tette fide ee cud abit the So teat hte tal 80 11 8 ICAN T TAKE AN IMAGE BECAUSE THE FILTER TRACK WON T LOCK INTO PLACE 80 INDEX OF TABLES TABLE 1 GENERAL MOSAICST 1 CHARACTERISTICS 5 TABLE 2 OBSERVING MODES AND MODE SPECIFIC CHARACTERISTICS eene 5 TABLE KPNO 4 METER CHARACTERISTICS sees nnne 6 TABLE 4 EXPECTED 0 9 M CHARACTERISTICS 9s etie reete enean dn ded mb aea nes enu nna ge 6 TABLE 5 NORMAL MODE CCD OPERATING CHARACTERISTICS esses 14 TABLE 6 LOGAIN MODE CCD OPERATING CHARACTERISTICS 2 2420040000000000000000000000000 15 TABLE 7 EXPOSURE TIME CORRECTION FOR SHUTTER TIMING ERROR seien eene enne nnns 19 TABLE 8 SOME OF THE CURRENTLY AVAILABLE FILTERS AND APPROXIMATE COUNT RATES SEC FOR 20 MAG STAR 21 TABLE 9 DITHER FILES DEFINED TABLE 10 THE DEFAULT FILLGAP DITHER OFFSETS TABLE 11 THE DEFAULT 8Q DITHER eene sen an seran TABLE 12 APPROXIMATE DOME FLAT SETTINGS AND EXPOSURE TIMES sees eee enn nnne nnns 68 INDEX OF FIGURES FIGURE 1 THE DISPLAY ORIENTATION OF THE 16 SECTIONS OF THE MOSAIC 1 1 IMAGER eene 10 FIGURE 2 ORIENTATION AND LAYOUT OF THE CCDS IN THE MOSAIC FOCAL PLANE AT THE 4 METER T
37. ELESCOPE 11 FIGURE 3 QUANTUM EFFICIENCY OF E2V CCDS IN THE MOSAIC 1 1 IMAGER FIGURE PR ET FIGURE 5 TYPICAL FLAT FIELD IMAGE R BAND eese eene nennen enne FIGURE 6 VIGNETTING AS SEEN ON THE RIGHT EDGE OF CHIP 4 nnne nennen FIGURE 7 IMAGE OF FULL WELL SATURATED STARS SHOWING CROSSTALK AND THE TRAILING GHOST ANOMALY 15 FIGURE 8 LEFT THE MOSAIC 1 1 INSTRUMENT BEING VACUUM PUMPED eese 16 FIGURE 9 RIGHT THE MCCD GRAPHICAL USER INTERFACE eene enne 16 FIGURE 10 THE MONSOON DETECTOR HEAD ELECTRONICS BOX sees eee enne nennen enses 17 FIGURE 11 THE MOSAIC 1 1 COMPUTER RACK eese esee eene stets tastas eerie eere 18 FIGURE 12 THE BROAD BAND FILTER SET INCLUDING THE WHITE FILTER 22 FIGURE 13 THE SDSS I AND 2 FILTERS ALONG WITH WASHINGTON CAND M 22 FIGURE 14 THE CURRENT SET OF HA PLUS REDSHIFTED FILTERS sees eene enne nnn nennen nnn 23 FIGURE 15 THE BLUE WOLF RAYET FILTERS FOR CIII HE Il AND A CONTINUUM AT 4750 sese 23 FIGURE 16 THE OIII ON BAND AND OFF BAND FILTERS PLUS DDO 51 nennen nnne enne nnne 24 FIGURE 17 THE V BAND FILTER INSTALLED IN THE FILTER TRACK THE 2 TV GUIDER FILTERS ARE VISIBLE TO THE LOWER LEFT AND UPPER RIGHT OF THE SCIENCE FILTERS ee
38. Jannuzi s Reduction Guide http www noao edu noao noaodeep ReductionOpt frames html Various Publications SPIE ADASS A New Image Acquisition System for the Kitt Peak National Observatory Mosaic 1 Imager http ww noao edu kpno mosaic SPIE7735 117 pdf A New Wide Field Corrector for the Kitt Peak Mayall 4 m Jacoby 1998 SPIE 3355 721 http www noao edu noao meetings spie98 jacoby ps 10 2 0 The Mosaic Hardware 2 1 The Mosaic 1 1 CCDs The Mosaic 1 1 Imager features eight e2v Technologies CCDs that are 2048 serial or pixels row x 4096 parallel or pixels column 15 um pixel CCDs arranged as an 8192 x 8192 pixel detector array as shown in figure 1 The Mosaic 1 1 CCDs are read out through two amplifiers per chip simultaneously to 16 video inputs of a MONSOON Orange controller The resulting Mosaic array is a square about five inches on an edge The space between CCDs is about 1 2 mm in both row and column directions and corresponds to about 80 pixel gaps in the imaging area 1264 5 5 CCD 6 CCD 7 ccD 8 5 11 01 5 13 01 5 19 02 5 15 01 1 CCD 2 CCD 3 CCD 4 SN10 02 5 05 01 5 09 01 SN11 02 Figure 2 Orientation and layout of the CCDs in the Mosaic focal plane at the KPNO Mayall 4 meter telescope 124 0 mm NORTH All gaps are 1 2 mm 80 pixels The Mosaic 1 1 Imager is populated with thinned AR coated e2v CCDs The CCDs are a deep depletion var
39. K nohs ACTION nohs_newobs RiRGS headers DITSCHD 24da nmslznmslDramalnitz DONE OK DITSCMD_24dbtnmsltnmslDramaGpxSetAVP DONE OK SUCCESS 1 TASK nms1 ACTION nmsl_gpxSetAYP ARGS expID 2455493 0299305680043995 DITSCHD 24dcinmslznmslDramalnitz DONE OK DITSCMD_24dd nmsltnmslDramaGpxGetState DONE OK SUCCESS TASK nms ACTION nmsl_gpxGetState ARGS IGNORE DITSCHD 24ff nmslinmsllramalnitz DONE DITSCHD 2503 exit status 2DITS F SIGINT DITS Exited via exit handler with signal SIGINT lt lt ABANDONED gt gt home observer exec standards d sh at line 101 executing ditscmd nmsl nmsl_gpxStartExp If you were INTEGRATING you should do the following If you were NOT integrating you re probably OK to continue anyway pnd noao edu 20080312 Lobserver amp mosaici 4m exec M Figure 59 Procedure displayed in an xterm window when a script is aborted Be sure to follow the on screen instructions displayed 75 10 APPENDIX F GOTCHAS Below is a list of known bugs and features Most will be fixed soon 1 Never abort a dither script It crashes the system 2 Don t do several abort exposures in a row This will also crash the system Instead use Ctrl C in the xterm window where the script was executed to quit out of the script 3 If you edit and save the currently executed script it will kill the current script and exposure 4 No end of readout sound is available yet 5 Right now the maximu
40. MEF files IRAF V2 11 is required to run MSCRED As of September 1 2004 we are running IRAF V2 12 2a as well as MSCRED V4 8 on tan emerald and nutmeg The basic syntax for specifying an image in a MEF file to an IRAF task is filename extension where filename is the name of the file The fits extension does not need to be used The extension is the name of the image For the NOAO Mosaic data the eight CCD images have the names im1 through im8 but the simple 1 through 8 works too The extension position in the file where the first extension is 1 may also be used To access the global header for listing or editing the extension number is 0 i e filename 0 There is currently no wildcard notation for specifying a set of extensions So to apply an arbitrary IRAF command that takes a list of images you must either prepare an list or type the list explicitly or use the special MSCCMD command The task MSCCMD takes an IRAF command with the image list parameter replaced by the special string input The input list of Mosaic files will then be expanded to a list of image extensions Section 3 3 illustrates the use of MSCCMD with the HSELECT task 54 4 2 Displaying and Evaluating Images at the Telescope NOTE this section remains relevant for Mosaic 1 1 but is not up to date The next version will have updated information During observing a small set of IRAF commands are commonly used to examine the data This
41. MSCSTAT runs IMSTAT or each of the selected extensions in a list of Mosaic files To restrict the measurement to a region you use image sections that apply to all of the selected extensions For example to measure statistics at the center of a set of observations the command would be something like cl gt mscstat fits 900 1200 2000 2300 There was some discussion earlier concerning use of generic image tasks with the NOAO Mosaic data The tasks IMHEADER and HSELECT fall into this category The two important points to keep in mind are that you must specify either an extension name or the extension position and that the headers of an extension are the combination of the global header and the extension headers Often one does not need to list all the headers for all the extensions The image title and many keywords of interest are common to all the extensions Thus one of the following commands will be sufficient to get header information about an exposure or set of exposures cl imhead obj 1 1 Title listing cl imhead obj123 1 1 page Paged long listing cl hselect obj 1 SI filter exptime obstime yes If you need to list header information from all the extensions then you need to take the additional step of creating an file For example to get the default read noise and gain values for each CCD cl imextensions obj123 gt list123 cl hselect list123 I rdnoise gain yes Rather than create an list you can use MSCCMD
42. The next version will have updated information In many ways the real work of reducing Mosaic data comes when preparing to stack the images to make a final deep image free from gaps and artifacts Not only is there a premium on having well flattened data to begin with but one must also understand the relative photometric and sky level variations among the images in a dither set At any point in the final stacked image different frames will be making differing contributions Any differences in scaling will produce noticeable artifacts in the final sky background or zeropoint In practice we have found that the stacking works beautifully with data obtained under clear conditions and with no bright stars near the fields on the other hand we have found that simple reduction strategies produce very poorly stacked images if the shape of the sky over the field or scattered light contributions varied over the course of a dither sequence or over the course of the night used to define the sky flat The first step in stacking the reduced Mosaic images is to register them to a common coordinate system This is done with the MSCZERO and MSCCMATCH programs The MSCZERO routine can be used to set the coordinate system origin for any given image given a known position or even ad hoc position for any star MSCCMATCH produces a revised astrometric solution for each dithered image This is essential 61 because of small linear shifts during the dither process a
43. Unit displays all of the current telescope information To launch it simply double click on the icon on the Mayall 2 desktop labeled VDU 3 3 The Ins and Outs of Scripting How to make a script All Mosaic 1 1 images are taken by executing a script Yes even a test exposure There is a very easy to use script editor within the NOCS called the NGUI 39 NOAO Mosaic 1 1 CCD Camera Mayall 4m Telescope File Options nocsParamsInit lt INFO gt dummy nocs obj registered OK nocsParamsInit INFO dummy nocs lamp registered OK nocsParamsInit INFO dummy nocs telpost registered OK nocsParamsInit INFO dummy nocs telofft registered OK nocsParamsInit INFO dummy nocs focus registered OK nocsParamsInit INFO dummy nocs gpxps registered OK nocsParamsInit INFO dummy nocs scr registered OK nocsParamsInit INFO dummy nocs rbin registered OK nocsParamsInit INFO dummy nocs cbin registered OK Help nguiShowFilter 1 X U X U X ignore ignore X k1001 nguishowFilter Z X B X B Harris X ignore X ignore X k1002 nguishowFilter 3 X V X V Harris X ignore X ignore X k1003 nguiShowFilter 4 X X R Harris X ignore X ignore X k1004 nguiShowFilter 5 X I X I Nearly Mould X ignore X ignore X k1005 nguiShowFilter 6 X ha X ha H alpha X ignore X ignore k1009 nguishowFilter 7 X hal6 X hal6 H alpha l6nm X ignore X ignore X k1013 nguiShowFilter 8 X g X 9 5055 ignore X ignore X k1017 nguiShowFilter 9 X
44. Version 4 2 December 2010 Revision by Heidi Schweiker Steve Howell and Dave Sawyer With contributions from Buell Jannuzi Phil Daly George Jacoby Taft Armandroff Todd Boroson Jim DeVeny Steve Heathcote Tod Lauer Bob Marshall Phil Massey Rich Reed Frank Valdes David Vaughnn raw image of the Moon courtesy of the commissioning team as observed with the KPNO 4 m telescope and Mosaic 1 1 Send comments on the manual to Heidi Schweiker or Steve Howell TABLE OF CONTENTS 1 0 MOSAIC 1 1 OVERVIEW AT LEAST READ THIS 2 0 2 1 5 125 GENERAL CHARACTERISTICS eI et eid ve da deser 5 1 2 KPNO MAYALL 4 METER PARAMETERS 6 1 3 EXPECTED WIYN 0 9 METER FORMERLY KPNO 0 9 M 6 1 4 ALL OF THE COMMANDS THAT ARE LIKELY TO BE 7 1 5 WHAT S CHANGED WITH 112 8 1 6 INSTRUMENT AND DATA OVERVIEW 9 2 0 255 2255525 5556 6 60684666 11 2 1 THE MOSAIC ii onto iden teste a E a 11 2 2 usse detect REDE UU 16 2 3 THE DATA ACQUISITION SYSTEM tiit ds 17 2 4 THECCD SHUTTER remet et cas toes viens 19 2 5 THE FILTER davai evad
45. at settings and exposure times 68 9 0 APPENDIX E NOCS Menus and Windows in Detail Below are snapshots of various menus and windows within the NOCS system for reference AAA observer mosaicl 4m nocs status all Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking Checking directory data2 observer 20101023 mosaiclpan a 4m kpno noao eduztpanDaemon mosaicipan a 4m kpno noao eduzi panCapture mosaiclpan a 4m kpno noao eduspanProcAlg mosaiclpan a 4m kpno noao eduztpanSaver mosaici 4m kpno noao eduz msl mosaici 4m kpno noao eduz2mslSuper mosaici 4m kpno noao eduzzmslSent mosaicl 4m kpno noao eduttnics mosaici 4m kpno noao eduszntcs 2 mosaici 4m kpno noao eduzznohs mosaici 4m kpno no mosaicl 4m kpno noao eduggngui mosaici 4m kpno noao eduzzdhs mosaici 4m kpno noao eduzspvm mosaici 4m kpno noao edue super mosaici 4m kpno noao eduzzximtool mosaici 4m kpno noao eduz vncviewer mosaicidhs 01 4m kpno noao eduzzcollector NOCS mosaicidhs 01 4m kpno noao eduzzcollector Pani mosaicidhs 01 4m kpno noao eduzzmosdca mosaicidhs 01 4m kpno noao eduzzsmcmgr mosaicldhs 01 4m kpno noao eduttpxf s mosaicidhs 01 4m kpno noao eduzzpvm
46. ating characteristics Dark Signal SEN e pix hr HCTE 96 There is some crosstalk between video channels in the imaging system The video channels on a given CCD i e the left and right outputs have a crosstalk level of about 0 296 This is shown in Figure 7 as classic crosstalk The crosstalk between video channels from different CCDs is less than 0 196 for adjacent CCDs and insignificant for all other channels The imaging system also exhibits a trailing ghost anomaly where full well saturated stars produce a ghost image that trails the star in the readout direction i e along the row away from the output amplifier This anomaly is not currently understood and remains a feature of the system CCD2 EEs CCD1 Figure 7 Image of full well saturated stars showing the effects of crosstalk between CCD outputs and the trailing ghost anomaly 15 x The Dewar The Mosaic Dewar is a large 6 3 liter vacuum vessel Figure 8 that is radiatively and conductively coupled to the CCD chip mount The conductive coupling between the tank and the CCD chip mount has been tuned to allow the temperature of the CCDs to be regulated at around 110 C over a wide ambient temperature swing The CCD temperature is regulated by a Lakeshore temperature controller that is configured for a maximum heater power of five watts The hold time of the Dewar is typically 13 5 hours and must be filled by an observing technician at the start and
47. d mosaicidhs 01 4m kpno noao eduzzpvmgs mosaicl 4m kpno noao edut mecd 15174 DISPLAY gt localhost 10 0 Files mosaici 4m kpno noao edu home observer ngui and mosaicidhs 01 4m kpno noao eduz home observer ngui are synchronized observer mosaici 4m 1 RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING RUNNING X NOCS xterm 1 4816 4819 4855 5356 DISPLAY gt localhost 10 0 4856 4863 4972 4973 DISPLAY gt localhost 10 0 4857 4861 4968 DISPLAY gt localhost 10 0 4858 4864 4970 DISPLAY gt localhost 10 0 7781 DISPLAY gt localhost 10 0 7861 7872 9859 9860 9861 9862 DISPLAY gt localhost 10 0 8096 8112 8113 8114 DISPLAY gt localhost 10 0 8301 DISPLAY gt localhost 10 0 8756 DISPLAY gt localhost 10 0 9244 DISPLAY gt localhost 10 0 9824 DISPLAY gt localhost 10 0 11280 DISPLAY gt localhost 10 0 4276 4285 4503 4506 4509 4512 4515 4518 DISPLAY gt localhost 10 0 4373 DISPLAY gt localhost 10 0 4317 DISPLAY gt localhost 10 0 4522 DISPLAY gt localhost 10 0 4501 DISPLAY gt localhost 10 0 4806 DISPLAY gt localhost 10 0 4943 DISPLAY gt localhost 10 0 5901 DISPLAY gt localhost 10 0 4980 DISPLAY gt localhost 10 0 5226 DISPLAY gt
48. d filters use ADC in track mode with appropriate filter selected For flat fields and narrow band exposures use the null position or closest in wavelength broad band filter mode Vignetting Mosaic 1 1 is slightly wider N S than Mosaic 1 0 and shows a 6 light decrease at 100 columns from the north or south edge and a 15 decrease in light when 25 columns from the edge The vignetting is removed by flat fielding Table 3 KPNO 4 Meter Characteristics 13 Expected WIYN 0 9 Meter formerly KPNO 0 9 m Parameters Count Rates At UBVRI 20th mag U 2 B 14 V 15 R 16 I 9 e sec FOV 59 x59 XIMTOOL Orientation North left East up Scale 0 43 pixel Image quality PSF fairly constant across the field but a 20 30 focus unit tilt is present Typical focus 31000 at 10C 31050 for U change with temperature 80 units per degree C Table 4 Expected 0 9 m characteristics 14 ofthe Commands That Are Likely To Be Needed Observing Commands nocs status all displays the status of all NOCS processes nocs start stop all starts or stops the NOCS observing program nocs stop start mccd opens or closes the MCCD and ADC windows nocsMode logain sets the gain to logain mode nocsMode normal sets the gain to normal gain mode nocs set project after the program ID has been set in the NGUI this updates the headers nocs start stop ngui opens or closes the NGUI window nocs start stop ntcs opens or closes the t
49. des that the ADC system can be used 1 Null mode where the ADCs make no correction 2 Track mode where corrections are periodically updated and 3 Preset mode where the corrections are preset at the beginning of an exposure to be correct for the middle of the exposure but otherwise not moved We recommend using Track mode to improve the image quality witha minimum of attention to the ADC operations ADC Filter Mode In Modes 2 and 3 Track and Preset the positions of the prisms are dependent on the observing bandpass because the optimum corrections have a color dependent functionality Thus in using the ADC it is important to select the proper filter mode in the ADC GUI on mayall 2 Note that this is done automatically if filter verification prompts is not selected in the ADC GUI 28 While the ADC is not necessary to compensate for atmospheric dispersion when using narrow band filters the guide cameras have separate broad band filters See Section 2 7 that will see the effects of atmospheric dispersion Differential refraction between the guider and the science CCDs will change as a function of telescope position and will cause blurring for long exposures at high zenith distances if the ADC is set to Null Mode In this case the observer should select an ADC Filter Mode that encompasses both the narrow band filter and the TV camera filter bandpasses and select ADC mode 2 or 3 track or preset Note that this is done automaticall
50. e tnt VINEA TA 20 2 6 iet i f e d RO qiie Deb a REP a 20 2 7 OPERATION OF THE GUIDER TVS 25 2 0 CORRECTORS EE Te E RO D PLE E IS 26 2 9 ATMOSPHERIC DISPERSION CORRECTOR AT THE 4 M 28 3 0 out dre 31 Sil THE MOSAIC 1 1 COMPUTERS 31 3 2 STARTING UP THE SOFTWARES 31 9 3 THEANS AND OUTS OF SGRIPTING 39 224 TAKING AN IMAGE cte t 44 3 57 tet eas 48 3 6 SHUTTING THINGS DOWN AND RESTARTING 1 42 42 1 esee nnne 52 4 0 EVALUATING RECORDING AND REDUCING MOSAIC IMAGES 53 4 1 WORKING WITH MOSAIC 5 nnne inns nns 53 4 2 DISPLAYING AND EVALUATING IMAGES AT THE 5 55 4 3 EXAMINING THE DATA eie dere een ere eee os De er ere e 56 4 4 GETTING YOUR MOSAIC DATA 2 58 4 5 THE REDUCTION OF MOSAIC IMAGEG 2 s sssssssssessssessssessssesesesseseeseseessseesesessesesseseeasseessesasseeassesataeess 58 4 6 CALIBRATION DATA TO OBTAIN AT THE 5 59 4 7 BASIC REDUCTIONS
51. een and the Status line to the right of the countdown clock will display Integrating When the exposure is reading out the countdown clock will be orange and the Status line will display Reading Out When the data is being written to disk the countdown clock will be red negative numbers and the Status line will display Transferring Negative numbers are expected and OK The transfer should only take a few 3 seconds If it takes longer than this look in your xterm window or the text window in the NMSL to see if any errors or failures occurred If errors failures have occurred and your image did not automatically display in the DHS Ximtool window you may need to restart the NOCS The Data Handling System DHS After an exposure has read out and transferred you should see your image appear in the DHS Ximtool window where you can interact with the data There should also be Iraf window within the DHS VNC window it maybe minimized as cl click on the icon and click restore The DHS Paths amp Files tab is where you can change your image file prefix as well as the directory where your data is being stored To change these values type in the new information and be sure to click the corresponding Apply button see Figure 46 in Appendix E Note that there are 2 different direct lines on this tab one labeled Raw Image Directory and the other Processed Image Directory The raw directory is where your raw data
52. elescope control system interface nocs start stop nics opens or closes the instrument control window filterwheel etc Quick look Commands mscexam general tool for examining image mscdisplay display an entire Mosaic frame mscstat general tool for looking at image statistics mscfocus IRAF routine to quickly determine best focus from a focus sequence 1 5 What s Changed with Mosaic 1 1 The purpose of this short section is to provide a list of the major changes in Mosaic 1 1 commissioned October 2010 that will affect the user These changes are the areas of observing strategy data transfer and storage and operating the camera On a casual look a new Mosaic 1 1 image will appear to be nearly the same but don t be fooled it is not The new focal plane consists of eight e2v 2048 x 4096 CCDs and has essentially the same look as the old system However the CCDs are now read out using 16 amplifiers so the final MEF image will have 16 extensions not eight as in the previous camera The new Mosaic 1 1 images are a full 18 bit image large dynamic range linear to lt 0 5 up to 210 000 e and are 282 MB each The approximate bias level in normal gain mode is near 500 ADU and near 2500 ADU in logain mode In normal gain 1e DN the read noise is near five electrons and the CCDs are nearly blemish free a few bad columns in two edge devices The readout time is approximately 22 seconds and the display is very fast after that
53. emains relevant for Mosaic 1 1 but is not up to date The next version will have updated information A key assumption in traditional reduction of CCD images is that the pixel scale is uniform and that a properly reduced blank sky image will have a uniform and flat appearance This is not correct when the pixel scale varies over the field In the case of Mosaic the pixel scale decreases approximately quadratically from the field center with the pixels in the field corners being 6 smaller in the radial direction and 8 smaller in area given the complete astrometric description of the field Pixels in field corners thus would properly report only 92 of the sky level seen in the field center even with uniform sensitivity At the same time the same number of total photons would be detected from a star regardless of how many pixels the PSF would be distributed over Forcing the sky to be uniform over the image would have the damaging effect of causing the photometric zeropoint to vary from center to field corners by 8 Note that this effect is different from vignetting where the flux actually delivered to the image margins is less than that at the center an effect that is corrected by the flat field 60 In practice the photometric effect of the variable pixel scale can be ignored provided that the reduced images will be part of a dither sequence to be stacked later on As discussed in the next section prior to stacking the images they first mu
54. end of each night Several temperatures within the Dewar are monitored and displayed in the Mosaic MCCD Graphical User Interface GUI shown in Figure 9 The CCD temperature displayed highlighted in blue is the chip mount plate temperature the CCDs themselves are not monitored and this is typically 10 warmer than the CCDs themselves This temperature will remain constant within a few tenths of a degree as long as temperature control is maintained The CCD temperature display will turn red if the CCD temperature rises above 95 C as the CCD performance may be compromised above that temperature mccp configuration 2 01 0 05 E Shutter ready dark jambient 7 12 6 Filter U Harris 1001 Camera s 0 80 2 30 Dewar 2 176 6 CCD 1 106 7 4 35 3 Focus 8858 Power 5 38 4 ese Figure 8 left The Mosaic 1 1 instrument being vacuum pumped The Dewar is the silver cylinder in the center above and behind the MONSOON electronics box Figure 9 right The MCCD graphical user interface is used to monitor temperature sensors located in the Dewar and electronics 16 The Dewar tank is cooled to 170 C or cooler This temperature will begin to rise when LN2 is exhausted If the Dewar temperature rises above 160 C the temperature display will turn red and mountain personnel will be notified via automatic email notification that the Dewar needs to be filled 2 3 T
55. equence You can use the image modes to track the sky level but again one must be careful that the mode is not biased by bad pixels and defects You can for example calculate the average sky level for a dither sequence and then gave MSCSTACK a file specifying additive offsets for each image about this average At this stage you should also account for any photometric variations among the images MSCSTACK can also accept a file of multiplicative offsets These might be based on an atmospheric extinction curve on photometric nights or determined by comparing stars among the dither set Or you can specify a relatively representative image section and have MSCSTACK compute the modes The final stacking of the image by MSCSTACK can be done with any of the standard combining algorithms within the IRAF combine tasks Some of us prefer to use an average value with sigma rejection We also make complete use of the bad pixel map at this stage to eliminate known defects One might be tempted to use a simple median but in the limiting case of a large number of images this will only yield 80 of the signal to noise available from an average On the assumption that most vectors of pixels to be stacked will be valid an average with occasional rejection gives the best answer Going all the way through to this stage has produced final stacked images of variable quality depending on the conditions of the observation In non photometric conditions the sky may
56. es during both opening and closing are in the same direction so the exposure level is nearly constant over the array The motion of the shutter blades is along columns There is a shutter timing error that is very constant for exposure times greater than 0 2 seconds The shutter corrections are shown in Table 7 The user interface limits the exposure time to a minimum of 0 2 seconds to ensure good linearity The maximum exposure time allowed is 3600 seconds Field Location Exposure Time Correction East edge 0 030 seconds Center 0 023 seconds West edge 0 017 seconds Table 7 Exposure time correction for shutter timing error 19 2 5 The Filter Track The filter track holds 14 filters For each filter position there is a filter for the CCD field and two separate filters for the two TV fields Separate filters are used so that a narrow bandpass science filter does not constrain the observer to find very bright guide stars Normally one would use clear BK7 filters for the TV but one can use a red filter to minimize moonlight or match the science filter more accurately One might want to match the science filter at least approximately to minimize a guider drift Even at the 4 m residuals after the correction from the ADC are of order 0 1 0 2 arcsec This and all filter decisions must be made ahead of time as the filters can only be changed during the day by a qualified observing technician Adapters exist to al
57. escope nor the guide TVs should require a focus change when switching between filters There is one exception the 504 U filter k1001 for which there is a focus offset A list of all available filters and their properties can be found at http www noao edu kpno mosaic filters Note that for the post processing command to display the correct on the fly flat the official filter name must be specified in the correct parameter set The official names can be found at 20 http www noao edu kpno mosaic filters filter names 4 m 0 9 m Filter TV Peak Central FWHM e s Central FWHM e s T9o Wave Wave U 58612 79 5 3577 646 35 3577 647 2 B BG 38 69 3 4360 990 330 4360 990 14 V BK 7 88 4 5370 940 340 5370 940 15 R RG 86 2 6440 1510 410 6440 1510 16 610 I 7 93 9 8220 1930 225 8220 1930 9 BK 7 94 3 6569 80 6575 80 H 4 BK 7 91 2 6611 81 6615 81 8 7 89 5 6650 81 6656 81 12 7 86 1 6692 81 6695 81 16 51 7 90 7 6730 80 6736 80 SDSS g BK 7 90 2 4813 1537 4813 1537 SDSS BK 7 91 8 6287 1468 6287 1468 SDSS i BK 7 94 6 7732 1548 7732 1548 SDSS z BK 7 94 8 9400 2000 9400 2000 01 2 BK 7 75 2 5021 55 5027 53 29 2 7 90 5 5305 241 5305 241 White BK 7 97 2 5600 6800 5600 6800 Wash BG 38 87 1 5100 1140 5100 1140 Wash C S8612 75 4 3860 10
58. escsscscsessessesesssssssessessssessesscsessessessssessesecsscsesscsecsscsesecsecseeeees 70 DHS SHARED MEMORY CACHE 70 DHS REAI TIME DISPLAY WINDOW ette e m metn e e D ERR 71 OPTIONS MENU SESS Rd Ri Vie OE BIE 71 NGUI MOSGRID CONFIGURATION WINDOW ssescsscssessescssessssesscssssesssassssssesssasssesscsscsesscsscsscsesecsecseseens 72 NGUI MOSDITHER CONFIGURATION WINDOW scscssessescssessssesscssssessssecseusessssssesscsscsessesscsscsesscsscaeseens 72 NGUI OBJECT CONFIGURATION WINDOW csscssescescssessssessessssesscssssesscsssssssessssssesscsscsessesscsscsesecsecseseens 72 TFLAT CONFIGURATION WINDOW tirir E E EE AEE AEEA EE E OAE 72 NGUI DFLAT CONFIGURATION WINDOW 73 NGUI TEST CONFIGURATION WINDOW scscescssesesessescssessssssessssessesssasssessesscssescsscsscsesscsecsscsesecsecseseens 73 NGUI DARK CONFIGURATION WINDOW 73 NGUI ZERO CONFIGURATION WINDOW csscsscssesessessesssessessssesssssssesscssssessesscsscsesscsscsesscsscsscsesscsecsesaens 74 NGUI FOCUS CONFIGURATION WINDOW csscssesesscssessesessessssesssssssessssessessesscasesesscsscsesecsscascsesscsecseseens 74 PROCEDURE DISPLAYED IN AN XTERM WINDOW WHEN A SCRIPT IS ABORTED
59. fset in time 67 8 0 APPENDIX D Flat Field Exposures Typical Dome flat field exposure times for each filter are given in Table 12 These exposures should produce pictures having 125 000 150 000 ADU per pixel to stay within the linear regime Note that each ADU represents 1 electron so there is plenty of signal with these recommendations To minimize thinking at the telescope we tried to use the maximum voltage settings when possible 4 m 53V 0 9 m 100 Note that these exposure times are for the normal gain setting For logain mode the exposure times are approximately one half the listed exposure time Flat Field Lamp Settings and Exposure Times Filter 4 meter 0 9 m Lamp Setting Exposure Time Lamp Setting Exposure Time U High 53V 35s High 100 Low 53V 60s Low 100 7 V Low 53V 50s Low 100 7 Low 53V 50s Low 100 Low 53V 55s Low 100 7 Halpha High 53V 1 35 Low 100 1 4 High 53V 1s Low 100 Halpha 8 High 53V Low 100 Halpha 16 High 53V 1 35 Low 100 High 53V 9s 7 29 7 Low 100 g Low 53V 38s Low 100 r Low 53V 50s Low 100 i Low 53V 60s Low 100 7 Zi Low 53V 80s Low 100 Wash M Low 53V 28s Low 100 DDO51 High 53V 2 5s Low 10096 VR Low 53V 30 Bw Low 53V 50 wh Low 53V Low 50 Us High 53V 22s Ud High 53V 25s Table 12 Approximate dome fl
60. he nocs start nohs unless it has indeed quit Typing nocs stop nohs will kill all instances of the nohs process that are running 11 4 I can t start the NOCS software If you tried clicking on the Start button on the Main Mosaic GUI and nothing happens the software may be in a bad state This command to start up the NOCS software can also be executed from an xterm window that is logged in to the mosaic1 computer Executing this from the command line will allow you to see if there are any errors or failures upon startup To startup the software type nocs start all The software first checks to be sure there is no other instance of itself currently running if there is then it will not start It s possible that it could be running on a different screen or that someone is running it remotely The software may also not have been shutdown cleanly leaving some processes still running When typing the above command and you get back an error claiming the software is already running you can double check what is and isn t running by typing nocs status all see Figure 44 above for the results If some processes are stopped and some are running it s likely that the software wasn t shut down cleanly You can stop and then restart the software by typing nocs stop all in the xterm window logged in to mosaic1 waiting approximately 30 seconds and then typing nocs start all in the same window This should successfully start the NOCS software
61. he Data Acquisition System The eight CCDs 16 video channels are read out using a MONSOON CCD controller that includes an Orange detector head electronics box DHE coupled to a Pixel Acquisition Node computer PAN through a Giga bit fiber link The DHE is located on the instrument see Figure 10 and the PAN mosaic1pan 4m at the 4 or 1 36 at the 0 9 m is located in the computer room see Figure 11 The MONSOON DHE PAN controls the detector voltages and clock sequences necessary to operate and read out the Mosaic CCDs In addition the data acquisition system includes a supervisor computer mosaic1 4m at the 4 m or mosaic1 36 at the 0 9 m that is the main user interface and a data handling computer mosaic1dhs 4m at the 4 m or mosaicidhs 36 at the 0 9 m These computers are also located in the computer room and share the same rack as the PAN computer Figure 10 The MONSOON Detector Head Electronics box with the access cover removed to reveal the chassis and PCB cards The DHE mounted on the Mosaic 1 1 instrument is shown installed at prime focus of the KPNO 4 meter 17 Figure 11 The Mosaic 1 1 computer rack containing the user interface and supervisor computer the Pixel Acquisition Node computer the Data Handling System computer and a spare computer The rack also contains a KVM switch and a remote power controller 18 2 4 The CCD Shutter The shutter consists of a pair of opposing sliding blades
62. he positions of the prisms Be assured the prisms are moved before the shutter opens it is just the updating of the GUI that is lower priority for the CPU 11 2 Loss of header information Occasionally header information will stop being populated to all extensions Sometimes this appears in the real time display as only 1 extension being displayed actually it is all 16 extensions displayed on top of each other To remedy this stop and restart the NOCS software 1 Click Stop in the Main Mosaic GUI 2 Wait for Ready at the top of the Main Mosaic GUI 3 Click Start in the Main Mosaic GUI 11 3 When do I type nocs start nohs When the NOCS system is started all necessary programs should be launched To see if all programs are up and ready type nocs status all in an xterm logged in to mosaic1 You should see a list of all processes followed by RUNNING see Figure 44 You should see that the nohs is running Upon the first execution of a script the nohs process usually dies for an unknown reason and your script is aborted with the following error message FAILURE TASK nohs ACTION nohs_newobs ARGS headers 78 You see if the nohs process is still running by typing nocs status all again This time it should say stopped If it indeed has died it can easily be restarted at any time by typing start nohs Note it is possible to have multiple nohs processes running so be careful not to type t
63. hs ACTION nohs_newobs ARGS headers If you see this error type nocs start nohs an xterm window that is logged in to mosaicl 14 Never abort a Focus sequence 15 Do not pause an exposure for longer than 1 of the entire exposure time as this can cause problems with the software If you need to pause for a longer time use Stop instead which will stop the exposure and read it out 16 Currently the ADCs need to be operated manually the filter mode does not change automatically when changing filters and does not prompt you to do so The ADCs do work and track well but more work needs to be done to have them update the filter mode correctly 17 In a mosdither sequence the NOCS system waits until after an image has readout before offsetting instead of offsetting during readout 77 11 APPENDIX TROUBLESHOOTING Listed below are some problems that have been seen with Mosaic In some cases we have known solutions in other cases the solutions are more magical 11 1 The ADC does not seem to be reacting fast enough The ADC GUI does not respond instantaneously to the motion of the ADC prisms There is a time delay If you restart ARCONS the GUI will occasionally not even show the normal positions of the prisms but as soon as you turn on either of the non null modes and or move the telescope the display will update Similarly you might start an exposure and hear the shutter open before you see the ADC GUI update t
64. iant from e2v for improved red response A 2 layer AR coating was chosen for improved blue response relative to the SITe chips used in the previous Mosaic imagers giving a big advantage in overall exposure time about 30 shorter for equal S N in U band Additionally the 2 layer coating provides a more uniform depth in all bands generally limited by U and B and has a flatter response curve to allow easier photometric transformations Figure 3 shows the e2v QE performance relative to the typical SITe CCD 11 e2v Quantum Efficiency 100 90 4 eed Typical SITe 2 5 05 01 2 5 09 02 2 SN10 02 2 SN11 01 2 SN11 02 2 SN13 01 gt 2 5 15 02 2 SN19 01 350 450 550 650 750 850 Wavelength nm Figure 3 Quantum Efficiency of e2v CCDs in the Mosaic 1 1 imager compared toa typical SITe device used in the former Mosaic 1 imager All eight chips have excellent cosmetic qualities and very similar performance characteristics Figures 4 5 show typical raw images of a bias and flat field The bias frames show an amplifier bounce at the beginning of each row read This bounce is at a 3 5 e level is very repeatable and is removed with a zero subtraction The flat field images show good pixel response uniformity and sensitivity There are three bad columns in the entire array and they are loca
65. ilable in the final stacking Some of us prefer to clear out the bad pixels right at the beginning of the CCDPROC process Re gridding the Mosaic images requires a method to calculate new pixels interpolated from the original ones One can select from any number of the standard IRAF interpolation routines however given the immense quantity of the data 62 involved we have always selected bilinear interpolation for speed considerations Unfortunately bilinear interpolation smoothes the noise slightly and as the new pixel grid beats against the original grid the noise in the tangent plane image shows bands of coherent noise structure This will be reduced somewhat in the final stacked image given the spatial de coherence of the images in the dither set Choosing the sinc interpolator significantly reduces the coherence but takes several times longer to process and may introduce a characteristic ringing around bad pixels Lastly as noted above MSCIMAGE has the option to correct the flux in the re gridded pixels for the variable pixel scale Use of this option should only be invoked when this information is preserved in the flattened images to begin with The final step is to combine the re projected dither set images using MSCSTACK This is the stage where careful attention must be paid to variations in zero point and sky level among the images Even on photometric nights the sky level is likely to change over the course of the dither s
66. ile integrating These fields are grayed out and disabled during readout and when idle When an exposure is paused you can only select Resume From there you can either continue with the exposure select Stop which will stop the exposure and readout or select Abort which will stop the exposure and discard the image One can also change the gain from the NMSL window by clicking on either the Normal Mode button or the Logain Mode button These buttons are grayed out and disabled during readout and integration but can be used when the system is idle See Table 2 in Section 1 1 for detector characteristics for normal and logain modes To abort a script click Ctrl C in the xterm window from which you executed the currently running script You should see the following message 46 moo NOCS xterm 1 DITSCHD 24d3 nohsznohsDramaMew bs DONE OK SUCCESS TASK nohs ACTION nohs_newobs RiRGS headers DITSCHD 24da nmslznmslDramalnitz DONE OK DITSCMD_24dbtnmsltnmslDramaGpxSetAVP DONE OK SUCCESS 1 TASK nms ACTION nmsl_gpxSetAYP ARGS exp1D 2455493 0298305680043995 DITSCHD 24dcinmslznmslDramalnitz DONE OK DITSCMD_24dd nmsltnmslDramaGpxGetState DONE OK SUCCESS TASK nms ACTION nmsl_gpxGetState ARGS IGNORE DITSCHD 24ff nmslinmsllramalnitz DONE DITSCHD 2503 exit status 2DITS F SIGINT DITS Exited via exit handler with signal SIGINT lt lt ABANDONED gt gt home observer exec standards d sh at line 101 executing d
67. in the sequence IV MSCCMATCH correct for rotations and minor zeropoint offsets I run this interactively to be sure the solutions are good V MSCIMAGE select a single image that will serve as a reference for all other images of this field All other images will then have the correct geometry for stacking and later comparison VI MSCSTACK add up the dithered sets VILIMCOPY up to this point you have created single images constructed from the five or more images in each of the dithered sets Because each image stared at a different piece of sky there will be offsets between the images and each image may have a unique size I use IMCOPY to select a region of each image that is common to all images In effect IMCOPY provides a fast method to shift all the final images to a common astrometric system using integer pixel shifts You may also use IMSHIFT to apply a fractional pixel shift but this introduces another interpolation that I have not found necessary 64 5 0 APPENDIX A Miscellaneous Software Commands Most commands that are executed through various GUI buttons within the NOCS can also be executed on the command line on mosaic1 For instance a start of the NOCS software can be executed either with the Start button on the Main Mosaic GUI or by issuing the command nocs start all from the command line when logged in as observer on mosaic1 Below are several commands that may useful nocs status all displays the status
68. into the image coordinates of the appropriate extension image Line and column plots also piece together the extensions at the particular line or column of the Mosaic display To enter the task after displaying an image the command is cl mscexam As with IMEXAMINE one may specify the Mosaic MEF filename to be examined and if it is not currently displayed it will be displayed using the current parameters of MSCDISPLAY To modify the radial plot parameters in MSCEXAMINE type cl rimexam2 which is analogous to rimexam for IMEXAMINE Or you can use the approved mechanism for modifying parameters within the EXAM tasks by typing g to switch the focus of the mouse cursor to the graphics window i gets you back to the image and typing e to edit the parameters of the sub task being execute 56 For evaluating focus sequence exposures you use MSCEXAMINE MSCFOCUS With the former you measure individual widths and keep track of the focus values yourself With MSCFOCUS which is a Mosaic version of KPNOFOCUS you mark the top exposure on any CCD for each star and the task measures all the exposures in the sequence and estimates the best focus value using information recorded in the data file To run MSCFOCUS on a displayed exposure just give the command witha file name it will display the exposure if needed cl gt mscfocus To measure pixel statistics you may use MSCEXAMINE or MSCSTAT a Mosaic version of IMSTAT
69. is written this is the line you need to change The processed directory is where any quick look pipeline processed data would be written if there were a quick look pipeline you can ignore this line At the bottom of the DHS Process Status tab see Figure 45 in Appendix E you can see the directory location and file name of images as they are written to the computer mosaic1 If this window turns red it is indicating that the DHS is in a bad state Most likely this will require a restart of the NOCS software At the bottom of the DHS window is an indication of the disk usage Mosaic files are large 282Mb for an unbinned image and although this is a Terabyte disk it can fill up quickly If the disk is full your images will not be saved In the DHS Real Time Display tab see Figure 48 in Appendix E there is a Display Enable button that allows you to control whether or not the data is automatically displayed upon readout Select this button to auto display deselect it to have no automatic display When an image is displayed there is a constant bias level that is subtracted from the auto displayed image This may occasionally make an image appear odd when automatically displayed Whether or not this on the fly bias subtraction is the cause 45 of an odd looking image can easily be determined by redisplaying the image in question You can turn this feature off in the DHS Real Time Display tab Occasionally during a sequence of expo
70. ishes to place objects on each of the eight Mosaic 1 1 CCDs The eight dithers in this script move the object sequentially onto each CCD in the following order 5 6 7 8 4 3 2 1 The script assumes the starting point has the object of interest at or near the center of the field of view 8Q dithers the telescope according to the offsets listed in Table 11 When finished the script returns the telescope to the starting position 49 80 553 799 0 553 0 553 0 553 1106 0 0 553 0 553 0 553 Table 11 The default 80 dither offsets Random This dither pattern moves the telescope to N random positions within a maximum offset of the user supplied RA and Dec limits Each of the positions are randomly generated and offset from the initial starting position but can be no larger than the RA and Dec limits specified The user sets how many random positions observations are desired and the script returns the telescope to the starting point when finished If Brownian motion is selected the random walk will eventually drift off center If Brownian motion is FALSE the random offsets are centered around the starting field position RAxDec Using user supplied RA DEC step sizes this script obtains N iterations of an N x M grid centered on the starting position The number of grid points in each iteration is an input value For example if you choose to do two iterations of 300 x
71. itscmd nmsl nmsl_gpxStartExp If you were INTEGRATING you should do the following If you were NOT integrating you re probably OK to continue anyway pnd noao edu 20080312 Lobserver amp mosaici 4m exec M Figure 41 The procedure for recovering from an aborted script Be sure to follow the on screen procedure before continuing The executed command in step 3 may be hard to read but should be ditscmd nohs nohs endobs 47 Image Display Images are automatically displayed in the Ximtool within the DHS window You can examine the data with Iraf within the DHS window or you can view the images on mayall 2 or emerald outside of the DHS window Iraf DS9 and Ximtool are all available on mayall 2 and emerald The mosaic1 data directory is mounted onto mayall 2 as data mosaic1 4m and emerald as data mosaic1 36 so your data is easily accessible 3 5 Dithering Dithering with Mosaic 1 1 One of the most powerful tools available to the Mosaic 1 1 user is the ability to perform dithers and group these together into grid patterns of dithers These tasks are accomplished by using the MOSdither and MOSgrid scripts offsets used in the dither are in units of arcseconds with x moving the telescope north and y moving the telescope east MOSdither Scripts MOSdither is a script that allows the user to obtain dithered observations of a field of view This type of observation might be used to eliminate the gaps in the f
72. lar to cameras of more modest size At the same time there are a number of important differences that we touch upon briefly here To start with Mosaic images are recorded in a special multi extension FITS format MEF In brief the Mosaic CCDs are saved as individual images grouped together as separate entities in a larger FITS file only at the end of the reduction are the CCDs assembled as a single large astronomical image Because of this special format most IRAF routines will not work directly on the full raw Mosaic files To provide for processing of the special Mosaic format as well as reduction and analysis tasks specific to Mosaic we have developed a set of IRAF routines available under the MSCRED package Almost all of the software tasks that we discuss in the following sections presume that you will be working within this environment A key factor that drives both the data taking and reduction of Mosaic images is the presumption that the final astronomical exposure will be built from a number of Mosaic images obtained by dithering the telescope This places strong demands on the quality of the data reduction to ensure the uniformity of the photometric response of the reduced image 4 4 Working with Mosaic Data Files NOTE this section remains relevant for Mosaic 1 1 but is not up to date The next version will have updated information An excellent summary of the Mosaic reduction routines is provided in the two guides written by
73. localhost 10 0 4022 DISPLAY gt localhost 10 0 4133 DISPLAY gt localhost 10 0 11342 fa Figure 44 NOCS status all when NOCS is up and running Data Handling System Supervisor Help Quit MM Process Status Shared Cache Real Tine Display Paths Files Ruit Update Show Activity Verbose pdate Clean SHC Page Usage nosaicidhs 01 nosaicldhs 01 Disk Usage 53 1 Connect Status Exp Status Figure 45 DHS Process Status window 69 Data Handling System Supervisor File Help Quit Process Status Shared Henory Cache Real Time Display Paths Files Paths Ports amp Nodes inage data2 observer 20101023 data2 observer 20101023 Zdhs lib ktn tcl dhs lib susproc Zdhs lib postproc SHC Page Usage nosaicldhs 01 nosaicidhs 01 Disk Usage 53 NENNEN Connect Status Exp Status Figure 46 DHS Paths amp Files window File Help Quit Process Status Shared Cache Real Tine Display Paths Files Shared Cache Status Delete All Update Status Process Next Process All m SHC Page Usage nosaicldhs 01 4 5 01 Disk Usage 53 NENNEN Connect Status Exp Status Figure 47 DHS Shared Memory Cache window 70 File Help Quit Process Status
74. low the use of 4 inch square 1 adaptor and 2 inch square 2 adaptors At the 0 9 m f 7 5 these 4 inch filters illuminate approximately 6K x 6K pixels 56 of the total sky area At the 4 m 4 inch filters illuminate approximately 5 5K x 5 5K pixels 46 of the total sky area The positioning of the filter track is highly repeatable However the acceleration of the track can occasionally dislodge dust particles between filter moves particularly if intervening movements have turned the filter upside down In all cases the filter track software moves the track in the direction that minimizes the distance moved to reach the requested filter position In addition to the 14 position filter track there is a manual slide that can hold a single filter of the same size 5 75 inches square This may be used for example to hold a bandpass filter when polarization filters are used in the track Use of an additional hand insert filter changes the focus At the 4 m changing inserting or removing this filter can only be done at the maintenance Southeast Annex position 2 6 Filters For Mosaic To fully utilize the field of view of the 8K x 8K filters must be 5 75 inches 146 mm square and have 5 43 inches 138 mm clear aperture The optimum thickness that preserves image quality over the entire field of view is 0 47 inches 12 0 mm AII KPNO Mosaic filters adhere to these specifications to maintain a parfocal condition Thus neither the tel
75. m offset that can be done is 45arcmin 6 The minimum exposure time is 0 2 seconds The maximum exposure time is 3600 seconds 7 The countdown timer and shutter get out of sync on longer exposures Not to worry the exposure will be of the correct length It is a problem with the synchronization with the displayed countdown timer 8 Don t change the gain mode during an integration or readout 9 Sometimes the DHS does not keep up with the images being taken and there seems to be a backlog of images that have been taken but not displayed or saved to disk Sometimes it seems to help move these images through the DHS if you select Update Status and Process Next on the Shared Memory Cache screen within the DHS 10 Do not open and use multiple script configurations simultaneously This could interfere with the current script being run and will certainly cause havoc with any scripts you are trying to write 11 Below is a snapshot of an image that is saturated for reference 76 Figure 60 A saturated image 12 Occasionally when an image reads out all amplifiers will display on top of one another which results in what looks like an image of just one amplifier This usually indicates that the headers were not populated To recover stop and restart the NOCS session using the Main Mosaic GUI 13 After starting the NOCS software upon executing the first script you may get an error like this FAILURE TASK no
76. n 7 7 focus 9550 shift 60 script FOCUSR sh New Integration Time s Change Integration Time Status INTEGRATING Mode normal Gain e ADU 1 00 Read Noise 5 0 Binning 1 1 Read Out 19 ADC Ready CCD Temp C 107 90 Figure 28 The NMSL GUI where most of the exposure information is displayed 2 NOAO Mosaic 1 1 CCD Camera Mayall 4m Telescope aka NGUI the script editor window N NOAO Mosaic 1 1 CCD Camera Mayall 4m Telescope File Options Help nocsParamsInit lt INFO gt dummy nocs obj registered OK nocsParamsInit lt INFO gt dummy nocs lamp registered inocsParamsInit lt INFO gt dummy nocs telpost registered OK nocsParamsInit lt INFO gt dummy nocs telofft registered DK inocsParamsInit lt INFO gt dummy nocs focus registered nocsParamsInit lt INFO gt dummy nocs gpxps registered inocsParamsInit lt INFO gt dummy nocs scr registered OK nocsParamsInit lt INFO gt dummy nocs rbin registered nocsParamsInit lt INFO gt dummy cbin registered nguiShowFilter 1 V U U ignore ignore k1001 nguiShowFilter 2 X B X B Harris ignore ignore X k1002 nguiShowFilter 3 V X V Harris ignore ignore X k1003 nguiShowFilter 4 X R X R Harris ignore X ignore X k1004 nguiShowFilter 5 X I X I Nearly Mould ignore ignore X k1005 nguiShowFilter 6 X ha X ha H alpha X ignore X ignore k1009 nguiShowFil
77. nce in angular displacement of a star between the center and corner of the Mosaic array is shown as a function of airmass for the 4 m and 0 9 m cameras Note that this effect does not vanish at the zenith as even the angular extent of the Mosaic field at the zenith is large enough for differential prismatic distortion to be present The particular curves shown are for an STP atmosphere The actual displacement will vary with temperature and in general will be slightly lower given the altitude of KPNO The prismatic distortion will also occur only parallel to a vector pointing to the horizon the center to corner displacement is thus meant only to be representative of typical angular distances within the Mosaic field Note that as a Mosaic field transits a range of airmasses as might occur in a dither sequence the differential prismatic distortion will vary over the sequence 66 7 0 APPENDIX Issues About Photometery NOTE We were unable to get any photometric data during commissioning of Mosaic 1 1 but will update this section after photometric data is obtained and analyzed The numbers here should be relatively close to the upgraded Mosaic with 10 better in the B and U passbands Look at Figure 3 in Section 2 to view the relatively QEs A common goal of observing with Mosaic is to derive photometric magnitudes for many objects Due to the wide field and multi CCD nature of Mosaic there are several issues that may affect the accurac
78. nd because of rotations introduced by differential atmospheric refraction across the field There are three important uses of MSCZERO The first is to set the coordinate zero point fairly accurately and then read back coordinates With a reference star one can obtain useful real time coordinates at the telescope The second use of MSCZERO is to identify a list of stars in one fiducial image that will be located in the other images in the dither set A third use is to reset the origins of the other images in the dither set to match the fiducial image in the event that the coordinate origin is lost or corrupted as happened a few times in our reductions The MSCZERO routine uses the known astrometric description of the Mosaic field so that the location of any star identified can be used to set a global origin In passing we note that the quality of the astrometric solution is excellent stars can be located to a fraction of a pixel 0 26 at the 4 m in all portions ofthe field MSCCMATCH uses the astrometric solution and recorded relative telescope offsets to locate the registration stars in a given image It can also be assisted by running the images through MSCZERO if this assumption fails for some reason Once a given star is located it is cross correlated with the same star in the fiducial image to calculate a positional offset You have the option to review the quality of the match to decide if it is acceptable The final offset is the average
79. nt1 expVector 1 checkReturnValue nmsl nmsl gpxSetAVP expVectorz1 set filter ditscmd nics nics init ditscmd nics nics filter Argument1 3 checkReturnValue nics nics filter 3 set dynamic expID EXPID MOSAIC_BIN msd OBJECT Observation 1 2 script DflatV sh ditscmd nmsl nmsl init ditscmd nmsl nmsl wgui Argument1 OBJECT Observation 1 2 script DflatV sh checkReturnValue nmsl nmsl wgui OBJECT Observation 1 2 script DflatV sh ditscmd nohs nohs init ditscmd nohs nohs newobs Argument1 NOCNUM 2 NOCNPOS 1 NOCOBJ DflatV NOCCBIN 1 NOCNO 1 NOCTOT 2 NOCS KY 0 NOCDHS OBJEC T NOCFSN k1003 NOCSCR DflatV NOHS Mosaic 1 1 NOCTIM 45 NOCRBIN 1 NOCFIL V NOCT YP OBJECT NOCID EXPID NOCSYS kpno_4m checkReturnValue nohs nohs_newobs headers ditscmd nmsl nmsl init ditscmd nmsl nmsl gpxSetAVP Argument1 expID EXPID checkReturnValue nmsl nmsl gpxSetAVP expID EXPID ditscmd nmsl nmsl init ditscmd nmsl nmsl gpxGetState Argument1 IGNORE checkReturnValue nmsl nmsl gpxGetState IGNORE ditscmd nmsl nmsl init ditscmd nmsl nmsl gpxStartExp checkReturnValue nmsl nmsl gpxStartExp none end observation sleep 2 ditscmd nohs nohs init ditscmd nohs nohs endobs checkReturnValue nohs nohs endobs none amp Finished script home observer exec DflatV sh ditscmd nmsl nmsl init ditscmd nmsl nmsl wgui Argument1 Finished script home observer exec DflatV sh 42 checkReturnValue nmsl nmsl
80. ocal plane or as a method of greater area coverage for your specific observing program MOSdither offers a variety of dither patterns to choose from These are summarized in Table 9 FillGap Performs a five point dither starting at the current position 8Q Places a central object in each of the eight CCDs RAxDec Takes N exposures in a user defined RA by DEC grid Random Takes N random location exposures within in a user defined RA by Dec box FromFile Dithers as instructed by a user supplied dither table Table 9 Dither files defined FillGap This is a minimal dither pattern providing five dither positions based on the telescope offsets listed in Table 10 This dither pattern is the old lauer dat dither pattern slightly adjusted to compensate for the larger chip gaps The last exposure is taken at the starting point and the telescope is left here at the end of the dither sequence The appearance of this dither pattern is shown in Figure 42 48 E Ka i s ao a B a Figure 42 An on sky map of a MOSgrid dither which used a 2 X 2 RADec grid where each point used a FillGap 5 point dither FillGap Dithers RA Dec 67 145 134 290 101 74 68 142 34 71 Table 10 The default FillGap dither offsets 80 This dither pattern is useful for observations such as photometric standard stars where the observer w
81. ocouple templ 106 599998 ocal Plate Temperature too LOW Temp 106 600 rnocouple temp1 106 300003 ocal Plate Temperature too LOW Temp 106 306 rmocouple templ 106 699997 ocal Plate Temperature too LOW Temp 106 700 rnocouple templ 106 400002 ocal Plate Temperature too LOW Temp 106 40c rnocouple 106 699997 ocal Plate Temperature too LOW Temp 106 706 rmocouple templ 106 400002 ocal Plate Temperature too LOW Temp 106 406 1 New Integration Time s DONE normal Gain 1 00 Read Noise e 5 O Binning 1 1 Read Out s 19 Set Normal Mode ADCReady 1 cco Temp 106 70 EEG USE AE Figure 49 NMSL Options menu 71 A Observation s ipt Name OBSERVATION CONFIGURATION mer Bl Vy viv Riv ify 54 nately ally rise ify us va vd 2x2 koeee 2 Cancel SCI MOSDITHER OBSERVATION CONFIGURATION T 8l viv iv haw hal6 v 4 rly ify Us Ud OBJECT Observation s OBSERVATION CONFIGURATION 2 1 na nate ally rs ily 93 Us 8 Figure 52 NGUI Object configuration window TFLAT Ohservation s Script Name OBSERVATION CONFIGURATION
82. of the individual offsets with a check for outliers This interactive approach gives the best confidence that the correct offsets are being used but the entire process can be run in an automated fashion Also MSCCMATCH can access a position catalog and interactively display the known stars on the Mosaic image to provide a totally independent solution for each dithered frame The penultimate step in stacking Mosaic images is to re grid them into common tangent plane projections using MSCIMAGE The use of a common projection aligned to the centers of the pixels is done so that the shift and stack step does not require any further re sampling Up to this point the individual CCD images are each stored in their own partition in the multi extensions FITS files MSCIMAGE pastes the individual CCDs into a large single FITS image accounting for their accurate relative positions and rotations given the astrometric description of the field MSCIMAGE further re grids the pixels into a tangent plane projection which yields pixels of essentially constant angular size over the extent of the Mosaic field This is also the best point to fold in knowledge of the bad pixel map The bad pixel map itself can be re gridded by MSCIMAGE giving the final routine MSCSTACK complete knowledge of where the bad pixels are If the bad pixels had been replaced prior to this point and had not been flagged in the Mosaic images themselves their locations would have been unava
83. oject MosDither MosGrid Exit dhe tletallata il metal ype tHetallsta mdbonfigTeli PieldSizelO 22 dotaluee O oi dhs tHetallta dhs tHetallata 20 dhsSendtietallatar lt H disSendietalatez HS dhsSondletaste 20 dhsSendletalate 0 dhsSendletalate 0 dhsSendtetalatat QD dhsSendhetaDat starting Usservation Nunber 1 send OxBaf3dc0 lt 126 120 sent 0538450 120 send metadata size 18178 sent metadata size i8176 send mdLonfig Oxbfab4620 sent ndConfig OxbFaG4G20 GUI v20101102 C 2010 AURA Contact Php pnd noss ou dhs thetallata Istat 0 DITSCHD Sal snohssnchsIravateutbs DONE 0K SUCCESS 1 TaSkEnchs RCTIDNenohz ARSS he 119010 1 DONE OK DITSCHD SainnelinwelleanatpsSethVPt TONE T SUCCESS T Skenrel ACTICNenme _coxSetAVP ARGS 0119000 Sazznnel niellranalnit DONE OK DISCHI SaS nnsl nnellramatpstetstate UNE T SUCCESS 1 Tfckenrel ACTICNemel epxtetState ff IDITSCHD Sabtrasl sns eanaTnit DONE OK stat stat 0 istav 0 stat LE176 istat SIZESZITE stet size 32776 stat waders elI 2455505 9 RGS INDRE 0 istat 0 277 istat 0 4064575313451052 sysexec tenp on set 53 19 Figure 25 The Mayall 2 left hand monitor with necessary Mosaic windows shown NGUI the Main Mosaic GUI xterms 33 The right hand monitor should look similar to this
84. one of which has rectangular slots open for the guide field The blades are attached to pneumatically driven cylinders to provide very fast control of the shutter This design allows the TV guide fields to be shuttered independently of the science field In the guide mode the closed shutter still allows the TV guide cameras to see the sky In the dark mode these fields are closed as well The acquisition software controls which mode the shutter remains in between exposures For object observations the shutter goes to the guide mode before the exposure begins For requested observation types of dark flat or zero the shutter goes to the dark mode before the exposure begins and remains in this mode after the exposure and readout are completed Note that the TV fields are always open when the shutter is open the different shutter modes only control the TV fields when the science shutter is closed If you have been taking darks flats or zeros you may need to set the shutter mode to guide in order to get light to the TV guide camera The time for the blades to move completely across the field is 23 msec There is a 115ms delay from the time the DHE issues the shutter open close command until the shutter actually moves This delay does not affect the exposure time since it is the same for both open and closing The DHE has a built in readout delay of 150 ms to allow the shutter to fully close before the CCDs are read out The motion of the shutter blad
85. rver users 2720 Nov 4 21 43 O3test sh rwxrw r x 1 observer users 13454 Nov 4 15 41 pndDitherNoTelescope sh rw rw r 1 observer users 76 Nov 5 00 10 standard sh rwxrw r x 1 observer users 2720 Nov 4 20 20 TESTR sh To change the standard sh file to become executable note the lacking x s at the beginning of the line simply type chmod standard sh 43 Download copy of NGUI Observers new to the upgraded Mosaic may find it useful to download NGUI to practice creating observing scripts The latest version of NGUI can be downloaded from the Mosaic web sites http www noao edu kpno mosaic A README file is also available from the link above indicating how to install this on your system The same version of NGUI is also available at the telescope for creating scripts on the fly Note that while this downloadable copy of NGUI is useful for practice in making scripts any script you create from this will likely not work at telescope NGUI uses the filter position number instead of the filter name in creating scripts and the list of filters in this demo version of NGUI may not be the same as what will be in the filter track during your run For example the R filter may be in position 4 in the demo version but in position 6 during your run So if you create a script using this demo version to take images in the R filter and ran that script at the telescope you may have images in some other filter Filters are changed frequentl
86. scripts will not execute a filter change 80
87. section describes these common commands While this section is oriented to examining the data at the telescope during the course of observing the tools described here would also be used when later reducing data The two commands DISPLAY and MSCDISPLAY are used to display the images in XIMTOOL or DS9 The DISPLAY task is used to display individual images in this context the individual CCDs in a Mosaic exposure There are many display options that are discussed in the help page The only special factor in using this task with the Mosaic data is that you must specify which image to display using the image extension syntax discussed previously As an example to display the central portion of extension im3 i e CCD 3 in the first frame and the whole image in the second frame cl display obj123 3 1 fill cl display obj123 3 2 fill The MSCDISPLAY task is based on DISPLAY with a number of specialized enhancements for displaying Mosaic data It displays the entire Mosaic observation in a single frame by filling each image in a tiled region of the frame buffer The default filling defined by the order parameter sub samples the image by uniform integer steps to fit the tile and then replicates pixels to scale to the full tile size The resolution is set by the frame buffer size defined by the stdimage variable An example command is cl mscdisplay obj123 1 Many ofthe parameters in MSCDISPLAY are the same as DISPLAY and there are also
88. ssseusausseseassas 37 FIGURE 34 AN XTERM WINDOW USEFUL FOR TYPING IN NOCS COMMANDS eene rennen nnns 38 FIGURE 35 FIGURE 36 FIGURE 37 FIGURE 38 FIGURE 39 FIGURE 40 FIGURE 41 FIGURE 42 FIGURE 43 FIGURE 44 FIGURE 45 FIGURE 46 FIGURE 47 FIGURE 48 FIGURE 49 FIGURE 50 FIGURE 51 FIGURE 52 FIGURE 53 FIGURE 54 FIGURE 55 FIGURE 56 FIGURE 57 FIGURE 58 FIGURE 59 FIGURE 60 TREMAN MONG vote SEAR UR det irte ea Rd este 38 THE TRUSS TEMPERATURE PROGRAM TRACKING THE TELESCOPE TRUSS TEMPERATURE 38 THE AUTOLOG CONTROL PANEL THE NGUI WITH BUTTONS AT THE BOTTOM FOR SCRIPT CONFIGURATION e eese 40 THE ZERO SCRIPT CONFIGURATION GUI USED TO CREATE SCRIPTS FOR TAKING BIASES 40 THE SET PROJECT GUI oneni rin eite ay ere eder ER RE HERR 44 THE PROCEDURE FOR RECOVERING FROM AN ABORTED SCRIPT s scescsscssesessessesessessesesesecasesesscasesescseeseseeaes 47 AN ON SKY MAP OF A MOSGRID DITHER 49 A PLOT SHOWING THE DIFFERENTIAL PRISMATIC DISTORTION DUE TO ATMOSPHERIC REFRACTION 66 NOCS STATUS ALL WHEN NOCS IS UP AND RUNNING sscsccscsscscsscssesescssescsessesecsesscsscsesscsecsecsesscsecssseens 69 DHS 55 STATUS WINDOW 69 DHS PATHS amp FILES WINDOW o csccscescsscsc
89. st be re gridded to a tangent plane projection which has pixels of essentially constant angular scale This is done with the MSCIMAGE task which re grids the pixels and has a flux conservation option that can scale the pixels photometrically by the associated area change If this function is disabled then improperly flattened images will have a uniform zero point restored with this option turned off In short the flat field already adjusted if inappropriately for the different pixel sizes so MSCIMAGE would then do no further adjustment Stars would be too bright in the corners of the flattened images but after re gridding their total fluxes would be scaled down to the appropriate values If the Mosaic images are to be analyzed individually however as might be done for standard star fields then after the flat field reductions are complete the differential scale effects must be restored The correction process is simple The scale at any point in the Mosaic field is already known from the astrometry so one could just calculate and multiply by a correction surface The final image would appear to have a variable sky level but would be photometrically uniform We also note that performing surface photometry on Mosaic images with their native sampling can cause biased results unless care is taken to track the changes in the pixel scale 4 9 Stacking Mosaic Images NOTE this section remains relevant for Mosaic 1 1 but is not up to date
90. sures usually ones with a very short integration time the images appear to get backlogged in the DHS The symptom is that an exposure will finish will readout with no errors or failures and then not be written to disk or automatically displayed in the DHS Ximtool window If the rest of the system is healthy i e no errors or failures the DHS window is not red there is plenty of space on disk it may be that the DHS is not keeping up with the data being taken The images are likely still available and simply need to be pushed through the system We ve found that sometimes this just requires another single exposure to be taken after the current sequence has finished However sometimes this requires more intervention In the DHS Shared Memory Cache tab click on Update Status You should see several lines 16 lines per image added to the text window above this button Often this will be enough to push the images through If it doesn t click on the Process Next button once If problems persist contact your support person or Instrument Scientist Exposure control commands One can change the integration time during an exposure To do so enter in a new exposure time in the New Integration Time s field on the NMSL window and click Change Integration Time This can only be done while an exposure is in progress and not during readout Pause Resume Abort and Stop are all also available from within the NMSL window but only available wh
91. t the 0 9 m we list the full compliment of computers for completeness All of the computers listed below are at the 4 m however there is an identical set of computers at the 0 9 m that are the same except for the naming convention 36 replaces 4m mayall 2 or mayall 3 a Mac mini computer in the 4 m control room from which all programs are launched emerald a Linux computer in the 0 9 m control room from which all programs are launched mosaic1 4m the main computer that runs the NOCS and co ordinates the data acquisition 1 4 the MONSOON pixel acquisition node PAN computer Presently called pan a because upon upgrading to Torrent controllers there will be a pan b 1 01 4 the main data handling system machine that ingests the data from the PAN and performs various data management tasks and produces the final FITS image on disk This image is transferred back to mosaic1 4m Presently called dhs 01 because upon upgrading to Torrent controllers there will be a dhs 02 1 4 a spare machine that includes a spare systran card This system can be reconfigured in minutes to replace any of the other systems that have failed 3 2 Starting up the Software The NOCS software runs on the computer mosaic1 4m at the 4 meter or mosaic1 36 at the 0 9 m but is displayed on the computer mayall 2 at the 4 m or emerald at the 0 9 m Mayall 2 is a Mac mini computer wi
92. ted on CCDs 5 and 8 that are positioned on the outer edges of the array 8 2 Figure 4 Typical bias image showing the amplifier bounce as the vertical bands apparent along the columns near the output amplifiers 12 Figure 5 Typical flat field image R band This raw image shows the good cosmetics and uniform response and sensitivity of the devices The rolled off edges are caused by filter vignetting Vignetting Mosaic 1 1 has slightly larger gaps between the top and bottom CCDs due to the packaging constraints of the new e2v CCDs Thus the N S dimension of Mosaic 1 1 s focal plane is slightly larger than the previous SITe CCD focal plane Due to this a slight vignetting is seen on the north and south edges of the array This vignetting is symmetric at each side and shows a 6 light decrease at 100 columns from the north or south edge and a 15 decrease in light when 25 columns in from an edge Figure 6 below shows a 20 line sum at the southern edge of CCD 4 segment 12 The vignetting is removed by flat fielding 13 ie X irafterm Figure 6 Vignetting as seen on the right edge of chip 4 There are two observing modes available normal and logain The normal mode is optimized for shorter read time and greater dynamic range The gain of the normal mode has been tuned to allow the full dynamic range of the MONSOON controller 18 bit ADCs to sample the full well capacity of
93. ter 7 X hal6 X hal6 H alphasl6nm X ignore X ignore X k1013 ngeiShowFilter 8 X g g SDSS X ignore X ignore k1017 nguiShowFilter 9 X X SDSS ignore X ignore X 1018 InguiShowFilter 10 X i X i SDSS ignore X ignore X 1019 nguiShowFilter 11 X 2 X z SDSS X ignore X ignore X k1020 nguiShowFilter 12 X 03 X VR Bernstein ignore ignore X k1040 nguiShowFilter 13 Us Us solid U 1044 X ignore ignore InguiShowFilter 14 X Ud X Ud Dey k1045 X ignore ignore V Brownian Motion Telescope Commands Filter Commands ark TwilightFlat Object MosGrid 14 Refresh Filter s Set Project Exit NGUI v20101011 C 2010 AURA Inc Contact Philip Daly pnd noao edu 2 Figure 29 NGUI provides the creation of scripts 35 3 VNC mosaic 1 4m monsoon the VNC window with DHS control and image display eoo mosaicl 4m 1 monsoon Handling System Supervisor AF XImtool Ver File Process Status Shared Henory Cache Real Tine Display Paths amp Update Show Activity 11518 4 7843 3 11368 7 8908 3 12263 1 8685 4 11594 56 9002 1 11725 9 3014 8 12249 2 7760 2 11438 8 8772 2 11677 8 8450 5 12405 5 8071 4 8071 4 10854 0 7764 5 Y 7764 5 11558 5 1 gt mscexam image00889 ecl displsy image00898 ERROR task displsu not found
94. ter after which it will compute a new display scaling and reload all the currently recorded data Thus a small value for the niterate parameter will update the scaling frequently and a large value will update more infrequently The trade off is that calculating the scaling takes a significant amount of time and causes the whole display to be reloaded while using only the first scaling based on just a little bit of data may result in poor scaling values Generally we recommend infrequent updates because of the very lengthy time required to display an entire image This use of MSCDISPLAY is only sensible if automatic displaying is disabled from the DCA GUI The MSCDISPLAY task is automatically started when a new image is reading out The IRAF Data Capture Agent DCA controls this default behavior Whether to display or not is controlled by the DCA user interface the DCA GUI See Section 4 9 4 3 Examining the Data Once you have displayed the Mosaic exposure you will need a few more commands specific to Mosaic to interact with the display to do such things as looking at exposure levels checking the focus and so on Just as we have written MSCDISPLAY as a special version of DISPLAY we provide the MSCEXAMINE routine as an analog of the standard IMEXAMINE to allow for interactive examination of Mosaic images MSCEXAMINE is essentially the same as the standard IMEXAMINE task except that it translates the cursor position in a tiled mosaic display
95. th 3 monitors and a small web camera Emerald is a Linux computer with 2 monitors To launch the necessary windows and start up the system double click on the 31 Mosaic icon Figure 22 on the desktop of mayall 2 or emerald This will bring up the Main Mosaic GUI Figure 23 MOSAIC Figure 22 The Mosaic Desktop Icon to launch the Main Mosaic GUI O08 08 X Mosa Mosaic Menu Ready Start Stop Autolog CCD GUI 2 Figure 23 Main Mosaic GUI Click on Start to start the NOCS software this is equivalent to typing nocs start all on 1 This will bring up several windows many of which will be minimized on the dock at the bottom of the monitor The last window to appear will be the NGUI or script editor window titled NOAO Mosaic 1 1 CCD Camera Note that when starting the NOCS software it checks to see if the software is running elsewhere first The software cannot be started locally if it is already running While the software loads the NOAO Mosaic Status All window see Figure 24 will update in real time as parts of the system are started Once everything is loaded this window will disappear 32 NOAO Mosaic Status All i exit 4 Figure 24 The NOCS Mosaic Status All window which disappears when the software is fully loaded When all of the windows are up the left hand monitor should look similar to this Finder File Edit 4 Thu21 52
96. the correct position the script will die with an error message indicating such 11 7 It takes too long for the primary mirror to settle during mosdither 4 m only During a mosdither sequence the NOCS software waits until your image is readout before offsetting to the new position In addition to the time to offset and setup on a new guide star there may also be a delay to starting your next exposure due to the primary mirror support system The primary mirror has an active support system aka 4MAPS If your offsets are in a mosdither sequence are large the support system may need to adjust some ofthe forces on the mirror which may take several seconds to update and display on the Observing Assistant s computer If you are doing a rapid fire program these delays can add up and cost your program a significant amount of time The Observing Assistant is able to control whether or not these updates occur during a mosdither sequence ask your friendly OA to disable this if necessary 11 8 I can t take an image because the filter track won t lock into place The NOCS system will not take an exposure unless a filter is in position any script will die following a filter move failure If there are problems with the filter track and a filter will not lock into place ie the locking pins will not insert there is a way to take data and ignore the filter position In the NGUI deselect the Filter Commands checkbox Note that if this is unchecked
97. the old correctors from scattering Nevertheless with the very wide fields being imaged bright stars are inevitable producing some ghosting from bright objects in certain fields Image quality The 4 m images are excellent across the entire 35 x35 field On good nights we have documented uniform 0 65 images in R There is no measurable focus gradient or PSF variation to within 10 The 0 9 m telescope is not as well corrected There is a small focus gradient across the 59 x59 field amounting to 20 30 focus units Images in the corners of the mosaic degrade somewhat especially in the lower left corner CCD 1 Also the corners of the field are slightly vignetted 5 10 by the internal telescope baffle Image Scale The 4 m scale is slightly variable 6 396 due to pincushion distortions from 0 261 per pixel at the center f 3 1 to 0 245 per pixel f 3 3 at the corner of the field The 0 9 m scale is 0 425 per pixel The spatial variation is small with the scale decreasing to 0 420 per pixel at the corner of the field 27 Ghost Pupil When using narrow band interference very blue e g U or red e g I z band filters at the 4 m a faint image of the telescope pupil falls on the CCD and has a diameter of about 10 arcmin Depending on the bandpass and construction of the filter this reflection typically manifests itself at lt 1 for broad band to 2 4 narrow band Ha U I z level above the background It arises
98. ting it might be time to check telescope focus To launch the program click on the Truss Temps button on the Main Mosaic GUI X Truss temp em Am 8 2C Figure 36 The Truss Temperature program tracking the telescope Truss temperature AUTOLOG The autolog is another useful program to have This is an auto generated observing log which is very versatile allowing you to edit or place comments in any section of 38 the log page To launch the autolog click on the Autolog button on the Main Mosaic GUI This will launch the KPNO Autolog Control Panel Figure 37 Be sure to enter exact path to your data directory select Mosaic as the instrument and click on Start Logging If Print log sheets automatically is selected a log page will be sent to the printer when the page is full KPNO 4meter Autolog Control Panel File Help Image directory data2 observer 20101024 Instrument Mosaic Start Logging ua Print log sheets automatically 10 10 99 R Marzke Tcl d 9 20 03 D Mills Figure 37 The Autolog Control Panel In the Image directory box you need to specify where the data is located The default location is data2 observer UTDATE Click on the Start Logging button to start the autolog program When any fits files are written to this directory they will be saved to the log The logs are then saved in your data directory as a postscript file VDU 4 m only The Video Display
99. u are using your own filters Our experience indicates that the array is geometrically very stable 4 7 Basic Reductions NOTE this section remains relevant for Mosaic 1 1 but is not up to date The next version will have updated information Almost all of the basic image reduction is done under the IRAF MSCRED package Before you get started you should be aware that the Mosaic multi extension FITS data format means that you will have to be careful to stick to the routines in MSCRED that can handle this format In many cases useful routines from CCDRED have been rewritten with the same name to be available in the MSCRED package IRAF routines in other packages can be used on one CCD at a time either in scripts or the command line but will not work directly on an entire mosaic image at once There is an MSCCMD routine that acts as an interpreter allowing you to use traditional IRAF routines on the Mosaic files if you need to use additional IRAF routines 59 One of the first things that you re likely to do is to stack sequences of zero dark and flat exposures to produce superimages to feed into CCDPROC On the assumption that the darks and zeros are all the same using ZEROCOMBINE and DARKCOMBINE presents no complications On the other hand you are likely to want to scale the flats by their modes and this at present can be tricky Because of the importance of image defects modes and other statistics can be biased by bad values Normall
100. ut moving the telescope from the desired position We find that we can guide at the 4 m on stars as faint as V 20 in full moon and at the 0 9 m to V 17 near full moon The TVs and guider are controlled by the telescope operator at the 4 m but by the observer at the 0 9 meter The observer must first select the N or S TV on the distribution panel See Figure 18 For the selected TV on the ICCD Control Panel 1 Turn the high voltage potentiometer completely counterclockwise 10 turn pot Toggle the power switch on on TV screen pixel defects will appear Neutral density switch should be down off Push the momentary button to enable high voltage Slowly turn the high voltage potentiometer clockwise monitoring TVs until guide stars appear Acquire a guidestar on the computer moss and initiate guiding consult the 0 9 m telescope user s guide http www noao edu 0 9m Tel Op html for details on step 6 9 When switching between the two TVs be sure to turn the high voltage potentiometer counterclockwise and turn off high voltage on the TV no longer in use 25 ICCD B SOUTH ICCD ANORTH x 39 110 H9IH 830109 9 METER ACQUISITION TV SYSTEM Figure 18 schematic drawing of the layout of the TV control panels at the 0 9 m Only the two leftmost panels in the lower rack are used with the Mosaic TVs The upper rack is used to select which TV video signal is seen on the monitor 2 8
101. y a bad pixel mask will be available in the Mosaic database to improve the situation If you are after the ultimate in flat fielding you can 1 estimate the mode in two passes where the first pass restricted the range of allowable pixel intensities to plausible values and 2 the second pass used the mode from the first pass to limit the range of allowable values to between zero and twice the initial mode With good zero dark and flat field images in hand the basic image reduction is done with the MSCRED version of CCDPROC If your data consists of a dither sequence that you intend to stack later we recommend that you do not interpolate over bad pixels This is more logically done downstream as we discuss later One of the last basic steps that you may attempt is to build a sky flat or illumination correction from a portion of your reduced data You could try going directly to a sky flat without any prior reduction with a dome flat or any other serviceable flat but working with roughly flattened data first allows for more accurate estimation of the mode in the presence of faint astronomical sources and further allows for better detection and rejection of biased regions of the images At the same time flat field reductions will produce wild values in the few defect regions so extra care is required when estimating modes or other statistics from flattened data 4 8 The Variable Pixel Scale and Zero Point Uniformity NOTE this section r
102. y and currently there is no way to get list of exact filter positions for your run in advance 3 4 Taking an Image Before taking any data you should check that your name and your program title go into the headers with the correct information Select Set Project at the bottom of the NGUI Set Project Parameter s Principal Investigator Heidi Schweiker Pls Email Address heidis noao edu Actual Observer s Schweiker AOs Email Address 4meter noao edu Observing Assistant KPNO Operator OAs Email Address 4meter noao edu Proposal Identifier 201 08 2006 Telescope System KPNO Mayall 4m Science Instrument Mosaic 1 1 Save Figure 40 The Set Project GUI 79 Enter the correct information and click Save Any changes you have made here do not take affect until either you restart the NOCS software or you specifically set the project To do this type set project xterm window that is logged into mosaic1 as observer All data is taken by executing a script from within the home observer exec directory See Section 3 4 for how to create a script The progress of a script is shown in the NOCS Status field of the NMSL window see Figure 28 In a sequence of exposures this is where you re current position in that sequence is displayed Finished script will appear when a script is complete 44 During an exposure the countdown clock will be gr
103. y if filter verification prompts is not selected on the ADC GUI The ADC GUI Control of the ADC prisms and modes is selected via the ADC GUI see Figure 21 The status of the ADC prisms also is displayed in the GUI window The primary user parameters in the GUI that concern the observer are the ADC Mode Null Track Preset and ADC Filter Mode U B V R I Bj ADC Configuration Filter Mode filter verification prompts R filter Help View Observing Mode w Nul Preset Track 60 004 2 359 94 v Re index E lt Last ADC adjustment occurred at 14 36 53 MST 2 Last re index at 16 33 35 Sep 1 Mls RA 0 14 27 59 DEC 16 23 38 7 Telescope azimuth 123 18 Zenith angle 72 38 Filter R Harris k1004 Moving ADC to optimal position please wait Figure 21 The ADC GUI When you change the filter you are using with the ADC in use you will be prompted to confirm that you want to change the operating mode of the ADC There is no beep or other sound warning that the system is waiting for your confirmation There is a pop up window that asks you to pick the appropriate mode If you would rather have the system automatically decide which the correct mode is you can unclick the filter verification prompts button in the GUI See Figure 21 The default mode for each filter is listed at http www noao edu kpno mosaic filters filter names Note that
104. y of one s results and in particular the hope of achieving 1 photometry CCD to CCD sensitivity differences While flat fields remove the gross sensitivity differences across the CCDs each CCD exhibits its own spectral response Relative to the B band U sensitivity varies by up to 10 and V by 5 from CCD to CCD Consequently the color terms for one CCD are not applicable to data taken with another CCD At a minimum therefore one must know the color terms for each CCD But there is another quirk If data are taken in dithered mode then some stars may have been exposed across several different CCDs each with different spectral properties Photometry from the stacked image will be sensitive to the combination of color terms Variations in spectral characteristics on a single CCD Even across a single CCD there are variations in sensitivity approaching 4 U relative to B This problem though is not new The old TI and Tektronix CCDs also exhibit variations almost as large Shutter corrections The large shutter for Mosaic is not perfectly accurate That is a command for a 1 second exposure will not open the shutter across the entire array for exactly 1 000 seconds As of November 2003 a one second exposure held the shutter open for 0 97 seconds at the top of the array and 0 96 seconds at the bottom This effect can be measured and calibrated out but it can also be avoided with longer exposures since the shutter error is a constant of

KPNO MOSAIC-1.1 IMAGER USER MANUAL Version: 4.2

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