Background

Installation of the DEIMOS tent mirror is a highly delicate operation which should ONLY be performed by a trained instrument technician. This procedure documents the steps followed during installation of the tent mirror in March 2005, led by Jeff Lewis and Matt Thompson of UCO/Lick Observatory.

Requirements

Procedure

  1. DEIMOS should already be in the appropriate position for access to the interior (ROTATVAL=-270). At this poition, the tent mirror faces up and the personnel access hatch is situated on the left side of the instrument (as viewed from behind the collimator).
  2. Band brake should already be set and tagged out.
  3. Using a slotted screwdriver, remove the personnel access hatch.
  4. Don protective gear (face masks, gloves, head covers, coats/bunny suits).
  5. Carefully enter the DEIMOS barrel. Be careful NOT to put weight onto the other access hatch, which is directly under you as you enter.
  6. Re-install the tent mirror by following these steps:
    1. Carefully remove the cable tie securing the piezo spring arm.
    2. Remove the two 10/32 screws from each of the two spring clamps at the side of the mirror mount.
    3. Carefully pass the tranfer case in through the access hatch. Note that you must tilt the case to pass it through the hatch; ensure that the thick end is DOWN.
    4. Remove the plexiglass cover from the transfer case.
    5. Using gloves, remove the tent mirror from the transfer case.
    6. Gently lower the tent mirror onto the V-shaped mounts.
    7. Gently rotate the optic (raise the thin edge) until the piezo ball is seated in the cone. Maintain gentle upward pressure on the thin edge of the optic to keep piezo properly seated.
    8. Attach spring tensioner to the glued-on block at the thick edge of the tent mirror wedge.
    9. Re-install the two 10/32 screws on each of the spring clamps. NOTE that the spring clamps should be installed such that the screws are to the inside of the clamp (see picture).
  7. Exit instrument and secure access hatch.
  8. Acquire alignment images to confirm proper alignment.
  9. Consult Lick if adjustments to alignment are required.
  10. Attach protective aluminum shield using thumbscrews.
  11. Ensure that witness samples are removed from dummy prior to reinstallation.
  12. Install the dummy tent mirror facing DOWN:
    1. Carefully remove the cable tie securing the piezo spring arm.
    2. Remove the two 10/32 screws from each of the two spring clamps at the side of the mirror mount.
    3. Raise the dummy tent mirror onto the V-shaped mounts, and hold the dummy in position (this is hard --- use knees to support dummy and/or trade off as needed). Be careful NOT to contact the real mirror with the dummy!
    4. Gently rotate the dummy (raise the thin edge) until the piezo ball is seated in the cone. Maintain gentle downward pressure on the thin edge of the optic to keep piezo properly seated.
    5. Attach spring tensioner to the glued-on block at the thick edge of the tent mirror wedge.
    6. Re-install the two 10/32 screws on each of the spring clamps. NOTE that the spring clamps should be installed such that the screws are to the inside of the clamp (see picture).
    7. Remove the aluminum shield from the real tent mirror.
  13. Exit instrument, remove all materials, and secure access personnel access hatch.

See Also