Home · Search · About ING · Astronomy · Public Information · Engineering

1. Please use the lone worker alarm when you are observing alone at the INT
2. For security reasons you must follow the instructions given to you by the support astronomer, duty engineer or WHT telescope operator (eg. abandoning site in bad weather or regarding the operation of the telescope and instrument)

1. Switch off lights on all floors, close the blind in the restroom.

2. In the control room, 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.

3. Make a visual inspection of the observing floor (and the balcony above the control room if the telescope is at ACCESS PARK) to check that the telescope is free to move e.g. no ladders or steps are close to the telescope or test instruments connected.

4. Clear any emergency overrides by pressing the RESET button close to the ENG/COMP button.

5. Turn on OIL PUMP from the engineering rack.

1. Ensure the telescope HA synchro pointers are at the "12:00" position (HA=0h).
2. Turn the DEC QM variable speed control fully clockwise.
3. Push the DEC QM button to release the slow motion clamps (engage Quick Motion).
4. Push and hold the DEC [+] button. This will move the telescope down towards the balcony.
5. At declination 100 degrees the HORIZON LIMIT alarm activates and the telescope will stop.
6. Push the ACCEPT button to mute the alarm.
7. In order to move to 106 degrees (position for filling the cryostat) turn and hold the LIMIT key-switch clockwise in the OR (override) position following the next few steps. The LIMIT key-switch causes the slow motion clamps to re-engage.
8. Push the DEC QM button to go back to Quick Motion.
9. Turn the DEC QM variable speed control to about half-way.
10. Push and hold the DEC [+] button; the telescope will then stop at about 106 degrees by itself; there is no danger in keeping the DEC [+] button pressed as the QM rate is half-way.
11. Now you may release the LIMIT key-switch.

Filling Cryostat (Balcony)

1. IMPORTANT! Wear safety helmet (with visor) and gloves when filling cryostats!
2. When the telescope is at ACCESS PARK, wheel the N2 dewar close to the platform.
3. Connect the dewar to earth; use the earthing point on the hand rail to the right of the telescope.
4. FULLY insert the filler tube into the cryostat.
5. On the dewar, CLOSE the VENT valve.
6. OPEN the DECANT valve.
7. OPEN the PRESSURE AUTO valve.
   n.b. Check the pressure does not exceed 20 psi.
8. If the dewar is low on liquid nitrogen, the PRESSURE MANUAL valve can be opened. Use precaution when doing this as the pressure can build up very quickly if the dewar is close to full.
9. Wait until liquid nitrogen is SEEN to be coming out of the cryostat.
10. CLOSE the DECANT valve and the PRESSURE valve(s).
11. IMPORTANT! OPEN the VENT valve. If this is forgotten, pressure can build up over time and burst the relief valve on the dewar.
12. Wait for the filler tube to warm up (until it is not rigid anymore) and remove it from the cryostat.
13. Note down when crostat was filled in the Logbook.

Moving the telescope out of ACCESS PARK (Engineering Rack)

1. Turn the DEC QM variable speed control fully clockwise.
2. Turn and hold the LIMIT key-switch clockwise in the OR (override) position following the next few steps. The LIMIT key-switch causes the slow motion clamps to re-engage.
3. Push the DEC QM button to go back to Quick Motion.
4. Push the DEC [-] button. This will move the telescope up and away from the balcony.
5. When declination is below 90 degrees you may release the LIMIT key-switch. If the audible alarm sounds, push the ACCEPT button to mute it.
6. Continue to push the DEC [-] button and stop at DEC=28d 45' (+/- 1 degree). This needs a bit of experimenting because the telescope will not stop immediately when you release the DEC [-] button. The telescope is now vertical.
7. Push the DEC SM button to re-engage the slow motion clamps.

1. Visually check that the telescope is near zenith park (i.e. vertical). The HA synchro position indicator pointers should be near the "12 O`Clock" position (HA=0h) and the DEC indicator pointers near the "9:50" position (DEC=29d). If the position indicators are some way off, move the telescope close to these positions using the HA and DEC [+]/[-] buttons on the engineering rack. Select quick motion (QM) if the telescope is a long way off position then go to slow motion (SM) to make the final adjustments. Both QM and SM buttons will be lit when SM is activated.

2. In the TCS User window, enter:

   USER> zeroset ha target  (or: zero ha tar)
   USER> zeroset dec target (or: zero dec tar)
       

3. n.b. These commands need to be typed in pair. If you type only one and then zeroset only that axis, it won't work. Using the HA and DEC [+]/[-] buttons with slow motion (SM) selected and the SM variable speed control to about half-way, move the telescope so that the synchro dial pointers MOVE THROUGH the zeroset marks in both axes.

   The TCS will beep if the zeroset is successful. The yellow LED's mounted above the synchro dials will momentarily flash also confirming that the telescope has been zeroset.

   Note: Occasionally when moving through the zeroset position the yellow LED will flash but the TCS computer does not beep to acknowledge the zeroset. If this happens, move back through the zeroset position and try again selecting a slower speed with the drive rate controls. If this also does not help then re-issue the zeroset commands on the TCS for both axes and repeat moving the telescope through the zeroset positions.

1. Check that the weather conditions allows for observations. Set the humidity audible alarm to either 75% or 90%.

2. On the UPPER SHUTTER PANEL, use RAISE MICRO until the MAIN OVERTRAVEL light underneath turns off.

3. If sunlight is seen hitting the inside of the dome, rotate the dome away from the sun using the DOME ROTATION cw (clockwise) and ccw (counter clockwise) buttons found just right of the upper shutter panel.

4. On the UPPER SHUTTER PANEL, push RAISE MAIN until the shutter stops moving.

5. Push and hold the PRIMARY MIRROR OPEN button. Check the mirror petals open fully (petals can be seen moving through the gap in the telescope structure).

6. Push the DOME VENT FAN button to enable dome ventilation. The red light will go OFF when the ventilator is on. You can also open the 'south doors' provided the TO did show it to you. Keep the south doors closed if the wind speed is higher than 40 km/h. Should the weather turn bad it is your responsibility to close this doors immediately.

7. Turn off the DOME LIGHTS from the console, the low-level dome lights (wall switch) and close the control room blind.

1. Put the telescope into Computer Mode by turning the COMP key-switch. The green section of the ENG/COMP push button switch should illuminate showing that Computer Mode has been selected. The system only switches to computer mode if the OIL PUMP is on, no emergency override is active (press the RESET button close to the ENG/COMP button) and if HA and DEC slow motion (SM) are active.

1. SYS>cmd INFODISP PREDICT ON
   This enables the automatic procedure for finding guide stars. Only valid for a rotator position of 180 degrees and nominal pointing (center of CCD 4). Every gocat command will now list a set of suitable guide stars in the TALKER window.

2. From the autoguider menu, select an integration time of 1 second and a guide window of 150 pixels (~40 arcseconds).

1. SYS> gocat xxxxxx (chose a suitable blank field)

2. SYS> guide on pixel 1032 512
   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. If the telescope is GUIDING and this button shows 'close loop', click on it and then click again to open the loop.

3. SYS> smartflat &
   A dialog box will pop up and tell the observer the needed exposure time. Exposures are taken by either clicking the `take this flat' button or using the command line, eg. SYS>sky 10 "Skyflat I 10s"
   Smartflat needs the camera shutter open!

4. Apply telescope offsets between successive exposures to enable removal of objects on the masterflat by i.e. median filtering: SYS>offset arc 10 10 (absolute offsets)

5. Once all twilight flats are done:

   click on the 'STOP' button on the autoguider GUI.

   Accept any error box messages and close the smartflat window.

If the star appears close to the window centre, the pointing is ok and you can skip the rest of this section. If not use the HANDSET to centre the star on the centre cross (in XY mode for the 180 deg. rotator position the cursors are reversed). Once centred type:

The rms of this solution is typically 0.01", type "Y" to accept.

1. SYS> gocat xxxxxx (chose a suitable standard)

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.

   Remember to set focus to the best value at end of focusrun (e.g. SYS>focus 43.98) and to repeat gocat if you need the target back in the centre.

3. Accept any error box messages and close the focusrun window.

4. You can use the Iraf command "wfc_starfocus" to compute the best focus value from the focusrun.

Object Handling:

Acquisition and Guiding:

Exposing:

Filters:

Examining data:

The IRAF interface on the Data Reduction System is used to examine the data. From the IRAF prompt, make sure you are in the right directory, i.e. cl>cd /obsdata/inte/20020319

To access pipeline reduced images, replace r123456.fit with qldata$q123456.fit

1. Bring the Telescope close to access park by typing:

   USER> park ap1

2. Push and hold the PRIMARY MIRROR CLOSE button. Check the mirror petals close fully (petals can be seen moving through a gap in the telescope structure).

3. Push the DOME VENT FAN STOP button to turn off dome ventilation. The red light will go on when ventilator is stopped. Close the 'south doors' when opened before.

4. Once the telescope is STOPPED, switch the TCS to engineering mode by typing:

   USER> eng

   The ENG/COMP push button should now be illuminated with an yellow light.

5. Close the dome shutter pushing LOWER MAIN until the shutter stops moving.

6. Push LOWER MICRO to fully close the shutter.

7. Fill the WFC cryostat following the same procedures as at the start of the night. Leave the telescope at access park.

8. Turn off OIL PUMP from the engineering rack. The OIL alarm goes off after a while; just push the ACCEPT button.

1. Insert the DDS3 (125m) tape in the drive /dev/rmt/0n or /dev/rmt/1n. A DDS3 tape (12GB) should be able to store 150 runs in fits format, or about 300 using tar.

2. Open a new xterm on the Data Reduction machine and change directory to where the data are stored.

3. prompt>tar cvf /dev/rmt/0n *.fit - writes all fit files to tape.

1. CCD cryostats : Initials and local time for filling the CCD(s).

2. Breakdown of observing time: Fill in any down-time that was encountered (bad weather, technical problems, etc.) and note the time lost.

• use of Intercom and Telephone
• safety precautions when using liquid nitrogen
• weather precautions, knowing when the dome must be closed
• observing at zenith distance between 57 and 70 degrees
• opening and closing the dome
• moving the telescope in engineering mode
• starting up and shutting down the observing system
• knowing about the most common faults and how to solve them
• writing your data to tape at the end of every night
• filling in fault reports
• filling in log book in control room
• producing the observing log
• filling in observing feedback form at the end of your run

---

Last Updated: 24 March 2004 Jürg Rey juerg@ing.iac.es