CFHT, Instruments, Spectroscopy, Gecko: The Coudé f/4 Spectrograph

Gecko: Setup of Triplet (Transfer) Lens

When Using the Coude Train


Check that:

  1. gain on the Slit Camera is down,
  2. gain on the Autoguider is down, and
  3. EM shutter is closed.



In the outer Coude room:

  1. Put the Power Supply ON (back of the room, power supply is on a shelf).
  2. Cover M7, ie, check and note the XY measurements of the mask, tilt the mask, and then cover M7.
  3. Remove flange + 4 cap screws under the lens (above the M7) - Be extra-careful not to drop any screw!
  4. Use the ladder, open the access door to the lenses.
  5. Use the switch to unlock the mechanism - something will start moving, but it does not have to go all the way.
  6. Use the other switch to rotate to the desired lens, then backup a little to have some play.
  7. Look from under the lens, center it by hand by pushing on the silver ring around the lens (this is easier if there is some backlash).
  8. Put back the flange + 4 screws - the flange should go in relatively easily - if not, re-adjust the silver ring.
  9. Lock the mechanism using the switch - keep the thing moving until the sound of the motor changes.
  10. Close the access door.
  11. Put the power supply to OFF.
  12. Uncover M7.
  13. Note which lens is now installed.
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Send comments to: Nadine Manset
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