INT Duty Engineer Checks

IDS with SDSU DAS and TV system

Rev 3.5



    FILL THE CRYOSTAT AFTER DOING THE DE CHECKS else the cryostat can empty out when the telescope slews.

  1. First check the Operations Logbook for any restrictions that may be still in force. Turn on the DOME LIGHTS from the console and raise the control room blind.

  2. Make a visual inspection of the observing floor to check that the telescope is free to move e.g. No ladders or steps are close to the telescope or test instruments connected.

  3. Push the LAMP TEST button on the engineering rack. Check that all used indicators are working (i.e. the ALARM lamps on the console and the push buttons on the engineering rack). Replace any defective lamps with new replacements (28v). There should be a supply of these in the cupboard in the control room.

  4. On the engineering rack, test dome rotation manually in both directions by holding down the DOME + then - button for a few seconds. This tests the integrity of the engineering TEM-L system.

  5. If the weather permits, open the dome shutter a small amount.

    Use RAISE MICRO (until the OVERTRAVEL indicator goes off) then push RAISE MAIN. To close the shutter, push LOWER MAIN and when the shutter stops moving down in fast motion, use LOWER MICRO to fully close the shutter.

    n.b. If the dome or shutter does NOT work from the engineering rack push buttons, check the manual controls on the large grey cabinet mounted on the dome. Access is via the balcony. The switches (some key operated) associated with the dome and shutters must be pointing to REMOTE. They may have been switched to LOCAL.


It is important to log out and restart the INT observing system and the TCS when doing the daily checks. This especially applies to the TCS and ICS computers where memory leaks can cause problems. This should also be done AFTER 12:00 (UT) so as to generate a new night LOG for the observations.

Observing system computer generic names:

inttcs     Telescope Control System (TCS)
intics     Instrument Control System (aka The Observing System) (ICS)
inttv      Slit viewing (or direct acquisition) TV CCD camera
intdrpc   Data Reduction PC

Associated with these computers there are 4 flat screen monitors. These being (left to right) :

  1. The TCS and slit-viewing TV camera (1 screen and a keyboard)
  2. The ICS (Observing System) (2 screens and a keyboard)
  3. The Data Reduction PC (1 screen and a keyboard)

Logging out from the ICS and DAS

Logging out from the TCS

Logging out from the TV system


NOTE The order of how the observing system is started is important. The TCS must be started before the ICS/observing system. Likewise, the DAS systems must be started before the Observing System.

TV start up

Logging into the TCS

          Check that the User and Infodisplay windows appear.




n.b. Always bring up the DAS before starting the ICS. When shutting down, do this in the reverse order.


* The CASS/IDS observing system is now ready to rock 'n' roll *


Start the oil oump

Zerosetting the telescope

Incremental focus position transducer (SONY) check

Testing the telescope in Computer Mode

Check that you can send commands to the TCS from the ICS.

This checks the communication link between the TCS and ICS computers. Test this by moving the focus.

Finalising the telescope checks


A major upgrade in re-commissioning the IDS. The slit/direct viewing TV acquistion camera now uses a WHT type TV/AG CCD head with an SDSU controller and replaces the old Westinghouse/Grinnell TV system that was in use for more than 20 years!


The Cass Autoguider consists of an RGO Peltier cooled CCD head fitted onto an X/Y table within the A&G box. The image processing is done using a VME system located in the CLIP CENTRE. Only limited testing can be done during the day, but the checks below should be sufficient to see if the autoguider is working.


When testing out the IDS, the normal checks would be:

  1. To take a bias frame to ensure that the CCD is healthy and
  2. To take a test arc lamp spectra.

Taking a BIAS frame

Move to the current image data directory

The DAS mimic will show what obsdata disc is in use. There are two OBSDATA discs : inta and intb. The data will be stored on the disc that has the most space available. A fresh directory is automatically created at midday (UT).

Displaying the bias frame

When the bias frame has read out, the computer will beep. After a minute or so, check in the observing LOG window that the image has been received labelled as a bias exposure and that the headers have been written. The images are stored as .fit files, each having a sequential run number e.g.

Examining the image


Setting up the A&G box

Setting up the IDS

Although the IDS has two camera ports (235 or 500), only the 235 is currently being offered. If at a later date both ports become available, the procedure to change between them can be found at: Changing between the IDS 235 and 500 cameras

During an IDS run do not change the positions of :

SYS> camshut open  (if the camera port shutter is CLOSED)

Set up a window

	Comments: If it is not the first observer's run do NOT change window size,
if you finally do, save previous values to be set back later

Take an exposure

Displaying the image

Using IMEXAM to check the IDS focus

Comments: This moves the two hartmanns to the desired positions.
It is important that the hartmanns are removed from the beam once focusing
is complete. The mimic will clearly show when a hartmann is still in.

SYS> complamps off
compmirror out


Filling the Cryostat(s) on the IDS


  1. IMPORTANT The liquid nitrogen dewar must be earthed to prevent static discharge. Clip the dewar earthing cable onto the grounding point. At Cass focus, a copper strap is provided for this on the mirror cell.
  2. FULLY insert the filler tube into the cryostat.
  3. Note The dewars are now left pressurised.   OPEN the BLUE dispensing valve.
  4. Wait until liquid nitrogen is SEEN to be coming out of the cryostat.
  5. CLOSE the DISPENSING valve.
  6. If the hose is of the metal type it can be removed immediately. If its a silicon rubber tube, wait a minute or so until it has defrosted and becomes flexible before removing it.

Before leaving the INT

  1. Back in the control room. Turn OFF the dome lights
  2. Don't forget to tick off the checks as completed and to sign off in the logbook

Document History

Rev 1.0 HTML version. First issued: Mar 11th 1999  John Mills
Rev 1.1 Corrections and additions made: Mar 25th 1999  John Mills
Rev 1.2 Cryostat filling procedure corrected : Apr 21st 1999  John Mills
Rev 1.3 Modified for UDAS usage, LN2 dewer eartling added : Oct 5th 2000  John Mills
Rev 1.4 Windowing command format corrected: Mar 15th 2001  John Mills
Rev 1.5 Minor changes made: Apr 27th 2001  John Mills
Rev 1.6 INTICS changed to lpss7: Oct 29th 2001  John Mills
Rev 1.7 Corrections and updates made: Feb 6th 2002  John Mills
Rev 1.8 Sony Focus encoder info added: May 29th 2002  John Mills
Rev 1.9 Removed machine names. Generic names only now: July 15th 2002  John Mills
Rev 2.0 Wording changed from 'Shutting down' to 'Logging out from' the INT Observing System : Sep 12th 2002  John Mills
Rev 3.0 A complete rewrite covering the new IDS observing and TV system: Aug 2006  John Mills
Rev 3.1 Updated TCS logon information: Sep 2006  Don Carlos Abrams
Rev 3.2 Instructed DEs not to change the slit width nor the central wavelength: Jan 2007  Don Carlos Abrams
Rev 3.3 Starting the new IDS TV camera using inttv1: Dec 2011  Jürg Rey
Rev 3.4 Position TVXY to required position: Jan 2012  Jürg Rey
Rev 3.5 TV loggin changed: Feb 2012  Jürg Rey