Working with INGRID

INGRID

INGRID (Isaac Newton Group Red Imaging Device) is a near-IR camera for use at the 4.2m WHT. At the heart of INGRID is a 1024x1024 Hawaii near-IR detector array for imaging from 0.8 to 2.5 microns, the pixel size is 0.238 arcsec.

startup

TCS:

USER> STATION CASS
USER> INSTRUMENT INGRID
USER> AGSELECT CASSE
Zeroset AZ and ALT

USER> AZ 298
USER> ALT 89
USER> ENG
USER> ZERO AZ TAR
USER> ZERO ALT TAR

USER> ZERO AZ ABS
USER> ZERO ALT ABS

USER> ZERO ROT ABS
USER> WAVELENGTH ...
USER> TEMP ...
USER> PRESS ...
USER> HUMI ...
USER> CAL LAST
USER> FOCUS 98.5

Autoguider:
With the new Ultradas system the usual setup for CASS autoguiding is available, so ICL>TO_PRAG works fine.
For guide stars just select the ING option on login.
Scripts for dithering while autoguiding are now available, with 2,3,4,5,6,7,8 positions. They are executed with SYS>ag_dither2 (for the 2-position one) from the pink Udas window.
The Autoguider preparation for using the scripts is as follows:

Find the guide star with GSS and send the probe to the position;
Place the star in the centre of the AG window adjusting the probe position by hand (see the layout drawn in the plastic cover on how to centre stars moving the probe). This is important as the dither offsets must fit into the window.
Do a FIELD with the AG (Do NOT start guiding or anything else).
Run the script from the SYS> prompt.

TV:
At Cass, Ingrid uses the large feed mirror (AGINGRID). To use AGCOMP for direct TV viewing (e.g. calibrate pointing), the large feed mirror must be out. While direct TV viewing no INGRID observing is possible.

Observing System:
ICL is basically only used to steer the AGINGRID mirror or move Autoguider filters or the Autoguider focus.
Instrument control & observing system are UltraDAS systems, and runs on Taurus.

preparation

Telescope focus:
The focus mechanism inside INGRID is only to compensate for collimator / camera distance i.e. instrument focus, not telescope focus. By correcting telescope focus errors with the instrument focus you risk distortion (astigmatism) in the image.
To begin a nights run, INGRID should be set to nominal focus (-750.0 microns) and a telescope focus run done to determine best value for telescope focus Once the telescope focus has been set, another focus run using the instrument focus can be done (if necessary) to optimize instrument focus.
We have found that the instrument focus is stable and should not change with either temp or filter.

Rotator Center:
You can determine the rotator center using the INGRID detector or the direct TV by rotating the field 180 degrees.

Calibrate telescope pointing:
Center the seven stars on the rotator center using the INGRID detector or the direct TV. Use USER> CAL FAINT for the INGRID detector. Be aware with the direct TV that the handset directions are turned 45 degrees. Don't worry, just center the stars on the rotator center. In any case turn the rotator tracking off (USER> ROT MOUNT xxx) before performing calibrate.

Aperture offset:
Do a GOCAT to the nearest faint calibrate star and take an INGRID glance exposure. Using the TCS HANDSET in APOFF mode center the star on the detector center, see the x-y coordinate system below. Then leave the TCS HANDSET and type the command USER> STORE AP 0. Finally repeat GOCAT and check the star is still on the detector center. The last aperture value was -12 18 (9/9/2001).

observing

Acquisition:
Imaging is easy - point and expose.

Make sure INGRID is fed by the large feed mirror ICL> AGINGRID. The rotator is usually kept tracking sky PA 180 (USER> ROT SKY 180). To copy the TCS info display on taurus.roque.ing.iac.es the startobssys sequence sends the command 'CLONE ON 161.72.6.56' to the TCS.
Observers usually define apertures for their dither and offset sky exposures. Here an example (sketch not in scale) with respect to the 4.06 x 4.06 arcminute field of view of the detector.

                   1

                   N
        +---------------------+         +------> X
        |                     |         |
        |                     |         |
        |                     |         |
        |                     |         v
        |       7             |         Y
        |           5         |
   3  E |          +          | W  4    USER> APERTURE 1 0 -300 (sky)
        |         6           |         USER> APERTURE 2 0 300 (sky)
        |             8       |         USER> APERTURE 3 -300 0 (sky)
        |                     |         USER> APERTURE 4 300 0 (sky)
        |                     |         USER> APERTURE 5 2 -2
        |                     |         USER> APERTURE 6 -2 2
        |                     |         USER> APERTURE 7 -7 -7
        +---------------------+         USER> APERTURE 8 7 7
                   S

                   2

data handling

Observing log:
The INGRID nightlog is produced from the obslog. Writing the data:
The data is written to DAT tape in the standard ING fashion. To do this, get a DDS3 tape. Open an xterm and change directory to the directory containing the data you want to be written to DAT tape. Attached to the Lupus and Auriga sparcs are DDS3 tape drives, the DAT tapes should be put in there and prepared for data by typing:
fitsinit
Follow the on-screen questions. Next the data should be written by typing:
fitsout
Again, follow the on-screen questions.

miscellaneous

Subject: Using the WHT TCS with INGRID
======================================

Operation of the WHT Telescope Control System (TCS) with 
INGRID is slightly different from its use with other WHT 
instruments.

This is because the TCS must serve telescope header 
information to the INGRID Observing System which runs on 
a Unix-based Sparc ('crater') rather than to the VAX-based 
system computer ('LPVF/LPVG') used for normal optical 
observations.

During a nights observing it is now possible (since version 
W12-0-6) to switch the TCS between Vax control (using DECNET 
communications) and Sparc control (using DRAMA communications), 
without the need to take the TCS down. This avoids the need 
to do any time-costly TCS recalibration.

Frank Gribbin has produced some notes on how to do the 
changeover. These may be found in the green "INGRID TO's
notes" folder in the WHT; additionally I have reproduced 
them below at the end of this email.

Other points to note:

1.  By default the TCS still comes up in DECNET comms 
    mode - ie the link to LPVF/G is active.

2.  DO NOT type 'TEL_LINK_TO_TCS' at the LPVF/G ICL
    prompt when running in DRAMA comms mode. This
    will totally stuff things up ! Instead, follow 
    the instructions laid down below.

3.  The INGRID Observing System does NOT provide 
    support for the "TCS info display". This display
    is now considered obsolete, its use having been
    superseded by the new TCS 'CLONE' command.

    To provide the INGRID Observer (sitting in front
    of 'taurus') with a TCS display type:

    CLONE ON 161.72.6.56

4.  The current changeover procedure is a bit fiddly
    and we (the software group) will aim to simplify
    things in due course.



WHT TCS Drama/Decnet communications   
-----------------------------------   

1) To start TCS with default DECnet communications, either

     (a) Start ICL system and allow it to start TCS.
         This starts DECnet communications to Vax system computer.
     (b) Log on to LPAS4 as WHT_LOGIN password on TO Xterm
         Select start. To start DECnet communications to system 
         computer type TEL_LINK_TO_TCS at ICL or start the ICL 
         system. 
     
     
2) To change to Drama communications (for INGRID)

   Drama communications are necessary for the INGRID control system 
   dither procedures and for collection of telescope headers. 

   With the TCS started as in (1) above : 
     (a) Log into LPAS4 as WHT_LOGIN 
     (b) Enter 
            OPTIONS 
         to select the options menu. 
     (c) Enter 
            COMMS 
         to select comms menu 
     (d) Enter 
            DRAMA 
         to select drama communications 
     (e) Enter 
            TELD
         to start the drama TELD task 
     (f) On ingrid system enter 
            tcsstat
         
         
3) To change to DECnet communications (for ICL+optical CCDs)

   DECnet communications are necessary for collection of telescope 
   header items by ICL and UltraDAS systems.  

   With Drama communications running as in (2) above 
     (a) Log into LPAS4 as WHT_LOGIN
     (b) Enter
            OPTIONS
         to select the options menu.
     (c) Enter
            COMMS
         to select comms menu
     (d) Enter
            DECNET
         to select DECnet communications. Don't worry if you get message 
         "Dtask failed to die". Ignore and continue. 
     (e) At ICL enter 
            TEL_LINK_TO_TCS 
     (f) Check link by issuing ICL command 
            PAGE 
         and note that TCS display page changes


4) To start TCS with DRAMA communications, either

     (a) Log on to LPAS4 as WHT_LOGIN password on TO Xterm
     (b) Enter 
            OPTIONS
          to select the options menu 
     (c) Enter 
            COMMS 
          to select communications menu
     (d) Enter 
            DRAMA 
           to select  drama communications 
     (e) Enter 
            MAIN 
         to go to main menu
     (f) Enter 
            START 
         to start the TCS and TELD drama task  
     
                              Version 2.1 
                              Frank Gribbin / Simon Rees
                              10-Apr-2000