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User Guide

  1. Starting the system
  2. INGRID real time display (RTD)
  3. INGRID mechanisms
  4. INGRID observing commands
  5. End of night
  6. Shutting down the system
  7. Important notes

1. Starting the system

  • Log on to the Sun workstation taurus (next to the ICL computer):
    • LOGIN: whtobs
      PASSWORD: provided by your support astronomer
    An openwindows session starts, and an xterm pink window (labelled "Central intelligence of observing system") and an orange xterm window with a number of tabs will appear. Also a netscape window appears, which shows the UltraDas Software Operations Manual (command dictionary included).
    Select the tab on the orange window corresponding to the DAS (data acquisition system) computer that controls INGRID (get its name from the white board above the ICL computer). It will be entitled whtdasx.
  • Start the data acquisition system:

    • Type obssys in the orange window. This defines the software to use and will then prompt you to select the observing system. Select the "manual camera selection", follow the instructions, and wait until the DAS> prompt appears.

    • Type DAS>startobssys to start the software. Wait until the prompt is back, then minimize this window (it is not needed until you shut down the system).

  • Start the system computer:

    • Type obssys in the pink window.
    • Follow the same procedure as you did for the orange DAS window and wait to get the prompt SYS> back.
    • Type SYS>startobssys
      This initializes the telescope control software (TCS) link, the INGRID mechanism controller and the INGRID SDSU controller, and brings up several new windows:
      • A real time display (RTD) control tool
      • An Ximtool window to display the data
      • The INGRID mechanism mimic.
        To get more detailed information about the INGRID mechanism wheels, select Control from the File menu.
      • An "identify" window.
        Enter your name and proposal identification.
      • The observing log.
        The log is automatically refreshed. To add comments about an observation click once with the mouse on the appropriate line; a box appears where you can type shorts comments.
      • The array info display window
      • The "talker" window. It displays messages from the observing system to the user.
  • Initialize the pupil stop wheel and the two filter wheels.
    SYS>fwheel1 ingrid datum;fwheel2 ingrid datum;pstop ingrid datum
  • If you want, you can bring up a telescope info display window. Type:
  • Set the array readout speed to slow:
    SYS>rspeed ingrid slow
  • To examine INGRID data:
    • Log on to whtdrpc1, the Fedora-based PC dedicated to quick look reduction (the monitor to the right of taurus):
      LOGIN: whtguest
      PASSWORD: provided by your support astronomer.
    • Open up an xgterm (type xgterm -sb&).
    • Open up a ds9 session (type ds9&).
    • Start an IRAF session (type cl or ncl) from the home directory (/home/whtguest), in the recently opened xgterm.
    • Type cl>ingrid_ql in IRAF, to start up the INGRID quick look reduction package.
    • Change to the disk and directory where the data is going to be stored ( e.g. cl>cd /obsdata/whta/20050429).

  • Now is a good moment to take two darks of the same exposure time and measure the INGRID array readout noise. To do this, put blanks in the light path, then take a couple of dark frames.
    • SYS>fwheel1 ingrid blank1
    • SYS>pstop ingrid blank
    • SYS>dark ingrid 2 "dark 2s a"
    • SYS>dark ingrid 2 "dark 2s b"
    • On lpss13, within the INGRID quick look package, type: in>ifindron and enter the filename of the two darks. The result is given in ADU.
    IMPORTANT: the readout noise value given in the image FITS headers is fixed, and regularly updated, but not derived from each specific image. Observers are therefore recommended to check the readout noise of their images.

The INGRID real time display (RTD) consists of two elements: a RTD control panel and an Ximtool window to display the data.
  1. RTD control panel. INGRID fits data files contain two extensions (e.g.[*,*,1] and[*,*,2]), which correspond to (i) the array readout after the reset process but before the integration (the pre-read, extension 1) and (ii) the readout of the array after the ntegration has finished (the post-read, extension 2). Click here for a more detailed explanation.

    The RTD control panel (see the image below) allows one to display (i) the post-read image, (ii) the pre-read image or (iii) the post-pre (=post minus pre) image of a particular run. Also, it is possible to display the result of subtracting one image from another (e.g. a sky subtracted image). This operation affects only the displayed data (i.e. only raw data is stored on disk).

    RTD Control Panel

    On the RTD control tool window, from top to bottom:

    • Observation Data Shows the file name of the image displayed in the Ximtool window.
    • Reference Data Shows the file name of the image loaded as reference data (see below).
    • Status Status of the RTD. It can be "scanning'' if the Data Detection is selected to be on (clicking on the corresponding diamond), or "data detection off'' if Data Detection is off.
    • Data Directory Shows the directory where the data are being stored.
    • Data Detection If you click on the on box, new images are automatically loaded into the RTD.
    • Display State This section offers several options to display the data, which are activated by clicking on the diamonds on the left:
      • OBS-REF Displays the post minus pre of the observation data minus the post minus pre of the reference data
      • OBS/REF pre Displays the pre-read of the observation/reference data
      • OBS/REF post Displays the post-read of the observation/reference data
      • OBS/REF post-pre Displays the post minus pre of the observation/reference data
    • Refresh Click on this button to refresh the display on the Ximtool window.
    • OBS->REF Load the current observation data as reference data.
    • Quit Click on this button to quit the RTD.
    • Load OBS/REF Data These buttons can be used to load any fits files in the Data Directory as observation data/reference data: type the file name of the image in the required box and click on the associated button.
    For example, in the figure shown above the post minus pre of the file is displayed (and no data has been loaded as a reference frame).
  1. Ximtool image display window. In addition to displaying an image, this window also has the facility to alert observers to saturation by turning pixels red if (a) the value of the post minus pre of the data set is higher than 28000 ADU or (b) the value in either the pre- or the post-read is higher than 43000 ADU. Note that non-linearity is ~± 2% over the range 0-12000 ADU (in the post-pre). More information is given here.

INGRID mechanisms comprises a pupil stop wheel, two filter wheels (one for narrow band filters and another one for broad band filters), the focus drive and a pupil imager. During normal science observations one broad or narrow filter might be in the beam, as well as an appropriate pupil stop to eliminate as much unwanted background radiation as possible, before it enters the camera.
  • Status of INGRID mechanisms

    The position of the filter wheels, the pupil stop wheel, the instrument internal focus and the pupil imager can be checked by means of the mechanisms mimic or the command line:
    INGRID mechanisms

    • The INGRID mechanism mimic summarizes the selected positions of the filter and pupil stop wheels, the pupil imager and the instrument internal focus value in microns.
      A graphical user interface (GUI) can be obtained from the File menu, by selecting Control. The selected positions in each wheel are coloured green.
    • In the pink instrument control system window, the command mchstat shows the status of the INGRID controller and all the mechanisms:
    • Click here to see the filters and pupil stops currently available in INGRID.

  • Moving INGRID mechanisms

    Mechanisms can be moved using either the GUI or the command line interface (pink window).

    • From the GUI

      • Filters and pupil stops. To move any of the three wheels, enable the GUI (clicking on square at the top-right) and then click on the filter/pupil stop you want in the beam. While moving, the whole wheel is coloured blue and the selected position yellow. When the wheel movement has finished the demanded filter turns green (success) or red (undefined position). If the latter occurs, you have to datum the corresponding wheel (click on the datum button or type e.g.: SYS>fwheel1 ingrid datum (or fwheel2, or pstop)). IMPORTANT: the motion of two wheels simultaneously can result in losing wheel accuracy and hence is not recommended.

      • Focus drive. For INGRID+NAOMI observations, the INGRID internal focus should be fixed at -1200 microns. (If it is not set to this value, type -1200 in the box and hit return.)

    • From the command line in the "pink window"

      • Filters. Individual filter wheel movements can be performed, for broad band and narrow band filters respectively, with the commands
        SYS> fwheel1 ingrid <filter name>
        SYS> fwheel2 ingrid <filter name> 

      • Pupil stops can be changed independently of filter movements with the command:
        SYS> pstop ingrid <pupil stop name>,
        where, for observations with NAOMI, <pupil stop name> may be:
        • naomi-obs, osca-obs Pupil stops with central obscurations, used for observations with NAOMI and OSCA respectively.
        • naomi-clr, osca-clr Pupil stops without central obscurations, used for observations with NAOMI and OSCA respectively.
        • clear No pupil stop in the beam.
        • blank1 Aluminium blank for dark frame acquisition.

        Consult your support astronomer about most appropriated pupil stop for your observations. For details on the dimensions of the pupil stops click here

      • INGRID focus drive. Type SYS>ifocus ingrid <position in microns>. This should be set to -1200 microns for INGRID+NAOMI observations.

      • Pupil imager. This is only used in engineering mode. For normal astronomical use the pupil imager must be out of the light beam. If you need the pupil imager to be removed, call your support astronomer or duty engineer.

A complete list and description of the commands can be found in the command dictionary of the UltraDas Software manual (except the dither command for INGRID+NAOMI, which is described below). A summary of the most commonly used commands is given here for a quick reference (where arguments are denoted by <>):

  • INGRID data acquisition commands
    • rmode ingrid mndr < Nr> < N coav>
      Sets the number of MNDR (multiple non-destructive reads) to Nr and the number of coaverages to N coav. Nr is the number of times that the array is read non-destructively prior to and after an integration. The array data from the Nr pre- and post-integration reads are averaged independently. Nr is an integer between 1 and 16; the default is 1, corresponding to "correlated double sampling". N coav is the number of accumulated exposures that are averaged and written as a single output file. See here for more details.

    • coave ingrid < N coav>
      Sets the number of coaverages to N coav.

    • multglance ingrid <N> < int time>
      This command can be used to use INGRID in "movie mode". It produces a sequence of <N> exposures of the required integration time. E.g.: multglance ingrid 999 2 produces a sequence of 999 2s exposures. The sequence can be finished by pressing control-C.

    • run ingrid <int time> <"title">
      Takes a run and saves it in The OBSTYPE header parameter is set to TARGET.
      E.g. run 8 "FS33 ks", performs an 8 second exposure and stores it in the output file (e.g. title of the fits file is set to "FS33 ks". If the number of coaverages has previously been set to 2 (i.e. coave ingrid 2 or rmode ingrid mndr 1 2) the command run 8 "FS33 ks" takes two 8 second exposures in succession, then coaverages the data before storing it in the output file (e.g.

    • dark ingrid <int time> <"title">
      Takes a run but sets the OBSTYPE header parameter to DARK.

    • flat ingrid <int time> <"title">
      Takes a run but sets the OBSTYPE header parameter to FLAT.

    • glance ingrid <int time>
      Takes an exposure and saves it in This file is overwritten when a new glance is taken.

    • scratch ingrid <k> < int time> <"title">
      Takes a run and saves it in: Note that k must be an integer between1 and 99. The scratch file is overwritten when a new scratch is taken with the same value of k.

    • multrun ingrid <m> <int time> <"title">
      Same as run but repeats the run sequence m times and generates m output files.

    • multflat ingrid <m> <int time> <"title">
      Same as flat but repeats the flat sequence m times and generates m output files.

    • multdark ingrid <m> <int time> <"title">
      Same as dark but repeats the dark sequence m times and generates m output files.

    • dither -intcount <integrations> -secs <int time> -offset <x offset> <y offset> -title <"title"> -5point <x dither offset> <y dither offset>
      The dither command is used to take exposures at different telescope positions while using the AO system NAOMI. Note that it should be used with sky PA = 0. Amongst other things, one can select the number of exposures at each dither point, the exposure time, the number of pointings and the size of the offsets. Eg.

      dither -intcount 2 -secs 10 -offset 0 0 -title "fs28 ks" -5point 4 4

      In this case, a five point dither is performed. For each ditherering position, 2 individual 10s exposures are performed (plus any coaveraging) and given the title "fs28 ks". The dither pattern consists of a central position, with four surrounding dither positions that are offset by ±4 arcsecs in x and y.

      See here for a detailed explanation about the dither command and its options.

      Before starting the dithered exposures, the AO loop should be closed by the SA. When performing the actual dithers, the script will (a) open the loop, (b) move the telescope, (c) move the wavefront sensor pickoff probe to reacquire the guide star, and (d) close the loop, before starting the next exposure.

  • INGRID diagnostic commands
    • detstat   Shows detector status and temperature of the monitoring points.
    • mchstat Shows mechanisms and INGRID controller status

  • TCS commands (usually performed by the TO)
    • user "ENTER APERTURE <number> <ra offset> <dec offset>"
      Defines the aperture < number> characterized by <ra offset> and <dec offset> arcsec offsets in RA and DEC respectively (e.g. user "ENTER APERTURE 1 -400 0").
    • aperture <number>
      Offsets the telescope according to the previously defined aperture.
    • offset arc <ra offset> <dec offset>
      Offsets the telescope by <ra offset> arcsec and <dec offset> arcsec in RA and DEC respectively from the nominal position.
    • gocat <object_name>
      Moves the telescope to the object <object_name> if this has previously been loaded into the TCS.
    • object <object_name> <ra(hh mm> < dec(dd mm> <equinox>
      Adds the object <object_name> to the catalogue.

5. End of the night

At the end of the night, please put blanks into the light path. It is not necessary to shut down the observing system.
  • Shut down the system computer:

    Type SYS>shutdownobssys on the pink window and wait until the prompt is back. Most of the windows will disappear (the RTD, log, mechanism mimic, array info window, talker, identify window).

  • Shut down the DAS:

    Type DAS>shutdownobssys
    on the tab corresponding to INGRID on the DAS orange window and wait until the prompt is back.

  • Close the TCS display window manually by selecting Exit from the File menu.
  • Close the Ximtool window by selecting Quit from the File menu.
  • Log out of INGRID's control computer by clicking the right mouse button on the background screen and selecting exit.
  • Do not kill the RTD display or control; this will generate error messages on taking images: Cannot open server connection on "inet:8001". To stop the RTD cleanly, type


  • To start the RTD, e.g. if you have stopped it or if the RTD control panel disappears, type the following in the pink window:


  • If the data acquisition mimic disappears, type the following in the pink window:


  • Remember to take dark frames of the same exposure time as your science frames. The dark level for the INGRID array can only be approximately be scaled with time. Also, it is dependent on the temperature of the array; therefore the dark level is not stable from night to night.

    • In the iraf session, within the INGRID quick look reduction package, use the task ilistdark to get a list of the exposure times of all your INGRID science frames. E.g.:
      in>ilistdark r*.fit
    • Put blanks into the light path.
    • Take the darks of the exposure times listed by ilistdark using the command dark. E.g.:

      SYS>dark ingrid 10 "dark 10s"

      This takes one dark frame of 10s exposure time and the title of the FITS image is set to "dark 10s". You can generate an observing script to get the dark frames for the exposure lengths needed and then execute it from the command line.

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Contact:  (INGRID Instrument Specialist)
Last modified: 17 June 2012