MDM Trouble Report for 2002 Jan 19

Telescope: 2.4m
Observer(s): John Thorstensen (Dartmouth)
Instrument: modspec + echelle

Problem(s) Encountered:
Several times during the night, apparently randomly, the RA
drive gear started howling very loudly -- either continuously or
at about a 2-second recurrence time -- and on the worst 
occasions the telescope started jumping around in RA, even 
binding up altogether once.  The problem was intermittent and
always went away.  Jules thinks it's a preload problem which
may be related to temperature.  For the record, it got down to 
about 3 degrees Celsius, then went up a couple degrees during
the night, and the problem was less frequent when the ambient
temperature was higher.

At one point when I was rotating the spectrograph the 
slit viewing optics somehow slipped out of position.  I just
pushed them back and continued, but the pushrod moved without
much resistance and I wonder if it might be tightened up a bit.
This would have been a real puzzler for a novice observer.

The rotator encoder at one point read crazy numbers for a while
(like -583) and then went back to normal.

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Submitted on 2002 Jan 19 [7:33:39]