Pressures and Pumping on UIST

Pressures and Pumping on UIST


Pressures are displayed in the electronics cabinet on the telescope, on the Edwards Active Gauge Controller (AGC) unit above the temperatures. These should read

  channel E-01 (only valid if channels 2 and 3 are above E-02)
  channel E-04
  channel E-07

Pumping UIST:

There is a Leybold Turbovac pump mounted on UIST; look for a cylindrical, silver block to the left of the coldhead. Check that the backing pumps in the coude room are on and that the backing line valve on the NW mirror cell panel is open.

To switch the turbo pump ON

  • Open the black speedivalve knob (to the left of the turbo pump) until you can see the red strip below the knob.
  • Go to the UIST electronics cabinet. The pump is controlled from a black panel (TURBOTRONIK NT 10) to the left of the Edwards AGC (red LED) pressure displays. The green POWER LED should be on. Press START – the orange ACCEL LED should come on. Wait a few minutes until the green NORMAL LED is lit. The pump will evacuate the pipe up to the gate valve on UIST.
  • Go back to UIST. You can now open the gate valve on UIST. At the front of the unit remove the pin in the valve, and flip the black lever 180 degrees until it is fully extended. Replace the pin.

IMPORTANT: Do not slew the telescope, even from Park to Zenith, while the pump is running.

To switch the turbo pump OFF (reverse of above)

  • Close the gate valve at the front of the unit.
  • Push the STOP on the NT 10 controller in the electronics rack and check that the NORMAL LED goes out.
  • Close the black speedivalve knob fully so that the red strip is again covered.

Before using the pump always clear with Tim Chuter or Erik Starman.