MDM Trouble Report for 2008 Sep 24

Telescope: 1.3m
Observer(s): Atlee & Barr (OSU)
Instrument: 4k Camera

Problem(s) Encountered:
Numerous problems with the telescope prevented viable 
data-taking for the entire night.  I have broken down the 
problems into two categories: telescope problems and control 
interface problems, with several subheadings related to the 
telescope.

Telescope Problems:
1) Telescope Focus
   a)Focus does not appear to be repeatable.  Focusing the
     telescope at a given position, slews to a new position and
     slewing back, the telescope is magically out of focus.
   b)Focus position appears to change spontaneously as the
     telescope slews/tracks across the sky.  Probably related 
     to (a).  Can be heard from control room.
   c)Changes noted in (b) are not reflected in software.  This
     required the focus to be sent home frequently to 
      unconfuse  the control interface.
2) Telescope Drives
  a)Error message associated with hitting east/west stops is
    uninformative: ERROR track ha motion program not executing
  b)Telescope appears to drift in Dec on occasion. Drift is
    small and slow, but both tracking motion and motion of 
    objects in question should be entirely sidereal.
  c)Dec drive motor emits high-pitched squeal during slew.
  d)RA drive motor emitted a similar high-pitched squeal, but
    rarely (twice)
  e)RA driver became confused (by issuing tx offset ha=X with X
    too large due to missing decimal point?) and tried to slew
    instead of tracking
  f)RA driver tried to track even after tracking shut off, or 
    with server & GUI both shut down
3) Miscellaneous
   a)Guide camera appears to have problems with internal 
     reflections.  Bright stars show one or more  ghost  images
     that move opposite the bright source.  (I.e. ghost moves
     south while telescope moves north.)  Observer might easily
     try to guide on a ghost image and become horribly confused
   b)4k camera seems to show reflections as well.  See, e.g.
     080924.0003 in which bright star & 3 reflections are spaced
     symmetrically around junction of the four chips.
   c)We hit the east stop block trying to slew to an object
     with HA ~-4 hours; Bob moved the block to allow slightly
     more freedom

Control Problems:
1)The control interface is in desperate need of a pointing
  model!  We found it impossible to slew the telescope more
  than 5-7 degrees at a step without becoming hopelessly lost.
2)Lost control of telescopes declination of two occasions:
  a)First was hand paddle only; corrected by slewing telescope
    to zenith and resetting the RA, Dec position
  b)Second was complete loss of control.  Hand paddle stopped
    responding, as did both  point to  and  offset  functions 
    of GUI.  Error message: ERROR point not conversing 
    dist=0.022 dra=0.001 ddec=-0.022.  Eventually resolved by 
    Bob changing paddle mode and forcing a slew south.  Limit
    on telescope tilt?
3)GUI hung & had to be killed when focus appeared to stall on 
  way home
  a)Focus was actually home, but GUI failed to update.  Forced
    refresh caused freeze.
4)HA displayed in GUI got set to ~-22:55 for a minute and then
  switched between 1:05 and -22:55 for a while before settling
  to 1:05
5)GUI reports attempts to send paddle to a mode it's already in
  in as an error: ERROR Paddle ACK not received

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Submitted on 2008 Sep 25 [2:52:03]