ideas for better optical alignment (Hua-Bai)

make new templates (DONE)

• make with blue foam, as marcus did
• use center ray at 1.35 meters
  • can check this with Marcus Runyan - see his E-mail
• don't forget to incorporate the tilt that Jeff and Giles introduced in 1999. need to decide whether to go with 5.5 degree or 6.5 degree rotation from nominal. (WILL DO BOTH)

find where center-ray is located on the physical tertiary

• find out how well we need to know this: (ANSWER: ~ 1 cm)
  • use beam-4 to translate tertiary until beam suffers
  • call this displacement x mm
• can we find center to x mm? perhaps this could be done using a separate, very accurate template of just the tertiary with center-ray marked (DONE: WE BUILT 12" DEPTH GAGE)
• remeasure the tertiary at Pole? (heidenhein digital depth gage?) (NOT NECESSARY)
• reconstruct the center from past measurements? (NOT NECESSARY)
  • call Bosma? can he tell us pos'n of vertex relative to mechanical center of tertiary?
  • would Greg have this info from back when he did the fit?
• sanity check: could it be flipped? (IT IS NOT FLIPPED)

2-4 degree alignment error in dewar axis

• how bad a problem is this?
  • use beam-4 to study aberrations? (NOT NECESSARY)
  • what is loss of surface accuracy due to this misalignment? (NOT NECESSARY TO KNOW)
• do we want to fix this? (YES, CAN FIX AT POLE)
  • is there any down-side to fixing this? (NO, BUT PAY ATTENTION TO BEAM CLEARANCE)
  • how do we fix it and can we fix it at Pole? (NEW LEGS FOR TRANSLATION STAGE; BUILD AT POLE)

at Pole

• use new template
• how do we adjust dewar translation in the two directions that are perpendicular to the optic axis? re-drill holes? (NEED TO THINK THROUGH. I WONDER IF IT IS NECESSARY GIVEN CHOPPER FREEDOM)
• use some combination of lasers and levels to get left/right tilt of the tertiary set properly? (WE HAVE A PLAN AND A LASER LEVEL; NEED TO CHECK INTO LASER AT POLE ALSO)