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Object catalogue handling

USER>incl <virgo> - Includes a user catalog named virgo.cat, stored in /int/cat. Check that the catalog has been loaded properly by listing it from the TCS using the command:

USER>out term

To add objects to the catalog type:
SYS> object name 12 20 30 -10 5 40 J2000
SYS> add

to move to the object type:
SYS> next - for the last one entered or
SYS> gocat name

However, objects added with the object/add sequence are passed directly to the object catalogue held on the TCS computer, and are not stored on the system computer.

TO write a catalogue back to disk use:
USER> output file int:[cat]newfile
which saves the file newfile.cat on a disk also visible to the system computer as /int/cat.


Initial TCS commands

USER>show focal - Show the focal station setup. If not set to PRIME/WFC, run the command
SYS>startobssys from the pink observing window.

Check that the PF rotator angle is set to 180° from the TCS DISPLAY window. This is the default rotator position. The automatic auto-guiding system will only work for this rotator position and the nominal aperture (object centred on CCD#4). To move the rotator, follow these instructions carefully.

USER>show aper - Lists the defined apertures. The list should read:

ap 0-251326 nominal aperture, object centred on CCD#4
ap 17045 centre object on CCD#1
ap 2357-1043 centre object on CCD#2
ap 3-701-10 centre object on CCD#3
ap 400 nominal aperture, object centred on CCD#4
ap 51316-368 centre object on AG-CCD (X=1032, Y=512)
ap 6251-326 centre object on RC (rotator centre)

You can change the default pointing aperture (ap 0) by entering e.g.
USER>enter ap 0 0 0
In this case, the telescope will point at the rotator centre instead of centre of CCD#4.
NB: Do NOT change the default apertures before calibrate.

New apertures can be defined by entering e.g.:
USER>ENTER AP 7 0 -350 or from the observers console with
SYS>cmd TCS USER "ENTER AP 7 0 -350"

Apertures > 0 are invoked by entering e.g.:
USER>AP 1 or from the observers console with
SYS>cmd TCS USER "AP 1"
and are only active until the next SYS>gocat 'source' command.

USER>focus 43.95 - Set focus to a 'good' value.

USER>calibrate last - Load the last TCS pointing model.


Twilight Sky-flats

There is an automatic procedure which, by continually reading the auto-guider chip, tells the observer what exposure time to use in order to achieve about 20000 counts:

Goto a blank field. Suitable fields are listed below:

BLANK104 25 46+54 09 03B1950
BLANK213 04 33+29 50 49B1950
BLANK316 47 52-15 17 44B1950
BLANK419 19 09+12 22 05B1950
BLANK521 26 54-08 51 41B1950
BLANK623 54 08+59 28 18B1950

SYS> guide on pixel 1032 512 - To start the auto-guider.
The guider is only used to measure the sky brightness, we don't want to guide. To open the guide loop click the 'open loop' button on the AG GUI.

SYS> smartflat &
A dialog box will pop up and tell the observer the needed exposure time. Exposures are taken by simply clicking the `take this flat' button. Remember to OPEN THE SHUTTER!
Once all twilight flats are done, type:

SYS> guide off


Single Star Calibrate

If the telescope pointing the previous night was acceptable, all you need to type is:
USER>cal last

However, if you experience problems finding guide-stars, it might be necessary to re-determine the pointing model. The first attempt should be to do a fast (this takes about 5 minutes) single star calibrate with the auto-guider:

SYS>agwin acq pos 1032 512 - Readout the auto-guider centre.

USER>cal - This sends the telescope to a suitable calibrate star. When the HANDSET menu appears, hit <ctrl-Z> to break out.

USER>aper 5 - Centre telescope pointing on the auto-guider.

On the auto-guider, mark the window centre by using the menu items on the auto-guider GUI (SETUP/TOGGLE CENTRE CROSS).

SYS>autotv on - Turn on continuous readout mode for auto-guider.

Use HANDSET to centre star on cross (in XY mode for the 180 deg. rotator position the cursors are reversed).

USER>point calibrate

USER>cal anal zero
The rms of this solution is typically 0.01", type "Y" to accept.


Seven Star Calibrate

After an instrument change or if the single star calibrate isn't giving a satisfactory result a seven star calibrate either automatic or manual is performed (this takes 20 to 30 minutes).

Automatic mode using autocal-script:

Before you start calibrate you should enter the parameter which affect
the calculation for the atmospheric refraction e.g.

USER> temp 6.7
      press 770
      humi 0.1
      wave 0.65               (example for Halpha narrow band filter,
                               if you use B then type 'wave 0.45')  
Make sure that the guiding is OFF (remember to turn off after flats). Start autocal from /home/intobs directory.

SYS>autocal
Ensure all pointing grid stars were found by the auto-guider - only then accept the pointing solution.

USER>cal anal
If the pointing solution is ok (in the order of rms < 5-6"), type "Y" to accept.

Manual mode:

Within normal calibrate you can't apply AP5 to move the stars to the
auto-guider, hence you have to redefine AP 0 to be
        
USER> enter ap 0 1065 -42     (the sum of the nominal AP 0 and AP 5)
        
Before you start calibrate you should enter the parameter which affect
the calculation for the atmospheric refraction e.g.

USER> temp 6.7
      press 770
      humi 0.1
      wave 0.65               (example for Halpha narrow band filter,
                               if you use B then type 'wave 0.45')  

On the auto-guider mark the window centre use the menu items on the
auto-guider GUI (SETUP/TOGGLE CENTRE CROSS).

SYS> autotv on       Turn on continuous readout mode for auto-guider.

USER> cal faint

      Use "handset" to centre all seven stars on the centre cross
      (in RaDec mode for the 180 deg. rotator position the cursors
      are reversed). If a star is centred press the 'DO' key.

Note the values in the log book and ** most important ** set the nominal
aperture back to the default by:

USER> enter ap 0 -251 326

Focusing the Telescope

To determine the best telescope focus the observer should select a suitable field (eg. one of the WFC photometric standard fields) and run a focus script:

  1. SYS>gocat sa101-427
  2. SYS>focusrun &

    A dialog box will pop up and the appropriate values may be filled in and a focusrun started. All "#n" exposures will be taken on the same frame with the a double spacing between #1 and #2.

    Make sure the first focus position is different from the actual focus position as otherwise focusrun won't start, due to a missing acknowledgment from the TCS.

    Remember to set focus to the best value at end of focusrun and to repeat gocat if you need the target back in the centre.


Finding Guide Stars

Automatic predicting guide stars with rotator at 180 degrees and nominal pointing:

SYS>cmd INFODISP PREDICT ON

SYS>gocat 'name'
See guide star positions in the TALKER window. You can then take these and start guiding with:

SYS>guide on pixel x y (with x y taken from the prediction)

Whenever you use a rotator position different from 180 degrees or an aperture different from nominal you need to run gsc_apm!

The HST guide star catalogue to V of approximately 15.5 magnitude is
stored on /catalogs/hstguide.sun. This 300 Mbyte file contains the complete
GSC catalogue and can be efficiently searched for guide stars for the WFC.

To run the software the following environment variables and alias have to
be set up in an observing system xterm window on LPSS13 or on the TO
window (these are automatically setup by startobssys but if you want to
run it from some other window then type

>setenv GSC_DATA /catalogs/hstguide.sun      - pointer to the HST catalogue 
>alias gsc_apm '/home/mike/soft/wfc/gsc_apm' - the latest version with 6+Nom
                                               beamswitch options

The program is usually invoked using command line options such as:

SYS>gsc_apm RaDec="10 30 0 -1 0 0" Rotpos=180 Equinox=J2000 Beam=N
SYS>gsc_apm Rotpos=90 Equinox=B1950 RaDec="21 30 11.3 12 10" Beam=C

 Command lines arguments are:
  
 RaDec="hh mm ss dd mm ss"
 RotPos=angle (180 default)
 Equinox=J2000 (or B1950)
 Beamswitch=N (or A,B,C,D,E,F)
  
        (A=centre of CCD#1, B=centre of CCD#2, 
         C=centre of CCD#3, D=centre of CCD#4
         E=centre of Autoguider
         F=rotator centre, located on CCD#4)

TCS/AutoGuider interface commands

SYS> focus 43.95            - set telescope focus [default best focus]

SYS> rotate sky 180         - move PF rotator to 180 degrees [default]

SYS> gocat 12+30            - go to faint pointing grid star

SYS> gocat N12+30           - go to bright pointing grid star

SYS> offset arc -30 30      - offsets telescope from current pointing
                              by -30 and 30 arcsec

SYS> autotv [on|off]        - continuous readout mode

SYS> field                  - do a field and search for potential guide objects

SYS> guide on star n        - pick "n"th brightest detected object and guide

SYS> guide on pixel x y     - guide on at position x,y on auto-guider CCD
                              default is to specify x y = -1 -1 which
                              cause A/G to guide on current guide star 
                              location
SYS> guide off              - turn guiding off
 
SYS> agwin acq pos x y      - set centre of field window for acquisition

SYS> autotime t             - set integration time "t" in ms.

Closed loop offsets
-------------------
You can offset by some arcseconds you may do this without opening
the guide loop using either aperture offsets on the TCS handset or
you can use the "tweak" command:

SYS>cmd TCS USER "TWEAK 10 10 0"

10 arcsec correspond to 27 pixels on the A/G (0.37"/pix) so you need
a guide window which can cope with the offset.

Below you find how the star on the AG will move using the TCS handset
in x-y APOFF mode:

    rot mount 180   S               rot mount 90    E
    +---------------+               +---------------+
    | |  ---> x     |               | |  ---> x     |
    | |             |               | |             |
  E | v  0.37"/pix  | W           N | v             | S
    | y             |               | y             |
    |               |               |               |
    +---------------+               +---------------+
            N                               W

Filter Wheel control

SYS> filter R                  - change to R filter

SYS>/int/S8-2/bin/wfc_mdb_gui  - enable access to WFC filter database (eg. set
                                 telescope focus offsets)

After exiting from gui type:

SYS>cmd MCA RESET              - to update the volatile use of the database
                                 and enable the changes.

Command dictionary for UltraDAS

Command dictionary for UltraDAS


[ Home | Telescope | Observing System | Alert | Faults | Commands | Quick Check-List]


This page last updated: June 14, 2000
Peter Sorensen (pms@ing.iac.es)