MDM Observatory 2.4m Telescope Observer's Report for 2001 Jun 24

Observer(s): John Thorstensen
Institution(s): Dartmouth

Instrument: modspec+echelle

Worked for 5 hours (off and on through the night)
Conditions were Mixed most of the night.
Problems were encountered, see the summary for details.

Seeing and Weather:
   Clouds all night.
   Beg: Seeing 1.5 arcsec, Patchy Clouds, Winds Moderate
   Mid: Seeing 1.5 arcsec, Patchy Clouds, Winds Light & Variable
   End: Seeing 1.5 arcsec, Patchy Clouds, Winds Calm

Observing Summary:

Heavy high cloud, but patchy enough to do some work in between
intervals of nearly complete obscuration of sky.  About an
hour of fairly clear weather around 10 PM.  Then heavier cloud,
closed slightly after midnight.  Sprinkle of rain 
around 2 AM.  Then, much to my surprise it cleared partially 
around 3 AM, and I was able to work until after twilight.  
[Hence the revised report, I'd already submitted figuring 
the night was lost.]
Problems: At HA = 5h 25m E and dec = +37, the telescope began to
slip east relative to the sky.  This was much too fast to guide
out -- it looked as if the track motors had cut out, but they 
hadn't, the telescope would intermittently pick up.  The problem
went away once lower HAs were reached. [I need to reach large
hour angles to squelch daily cycle count ambiguities in period
searches.]  During the slippage the RA readouts appeared to be
accurate (i.e., they were slipping, too.)
Also, around 11 PM the power dropped out twice in rapid 
succession for about 3 sec each time.  Everything crashed, then
started to reboot, then crashed again. Luckily there was no 
damage and I was back on the air after about 20 minutes.  I
was running on line power because of last night's experience 
with fluctuations in the generator voltage.

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Submitted on 2001 Jun 25 [4:59:25]
NOTE: This report replaces the previous 2.4m telescope
      observing report for 2001 Jun 24