MDM Trouble Report for 2009 Jan 29

Telescope: 2.4m
Observer(s): McGreer (Columbia)
Instrument: CCDS

Problem(s) Encountered:

At the beginning of the night, I set the pointing on a bright
star near zenith and then went to a target a couple hours west
of the meridian.  I waited several minutes for the telescope
to arrive, but it continually reported  Set+Track  for the RA.
When I tried to go to another guide star it seemed to be lost,
so I looked in the dome and it was pointing east at a very low
altitude.  I manually returned it to zenith and the pointing was
way off.  After restoring the pointing everything it worked
for the next few moves.

Three times over the remainder of the night I lost pointing,
though not quite as drastically as the first time.  On the later
occasions, I would find upon returning to zenith that the pointing
was off by about a degree in the E/W direction.  After resetting
the encoders it would work for a while.

It seemed that the
telescope would have difficulty reaching a position in the E/W
direction, watching the TCS I would see that the hour angle of
the telescope would be 10 seconds or so behind the desired
position and never seem to catch up.  This was solved, as in
the previous couple of nights, by hitting the STOP button,
moving a small distance away, and returning.

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Submitted on 2009 Jan 30 [6:47:24]