MDM Observatory 2.4m Telescope Observer's Report for 2001 Jun 28

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

Instrument: Modspec + Echelle CCD

Worked for 9 hours (all night)
Conditions were Non-Photometric most of the night.
Problems were encountered, see the summary for details.

Seeing and Weather:
   Beg: Seeing 1 arcsec, Cirrus, Winds Light & Variable
   Mid: Seeing 1 arcsec, Cirrus, Winds Light & Variable
   End: Seeing 0.8 arcsec, Patchy Clouds, Winds Light & Variable

Observing Summary:

Good weather, though non-photometric -- a little high cloud,
usually not noticeable at all. Often excellent seeing.  
Interestingly, the temperature profile on the A/C computer 
graph shows a very smooth decline through the night, which 
I bet correlates with the seeing.  CV periodand ephemeris work.
Ran on generator tonight, having learned my lesson.  Very light
wind from N later in night pushed fumes my way -- I love the
smell of propane in the morning!

The telescope RA drive is acting up very badly at times.  Twice
during the night it got stuck at some spot -- it would go east,
but not go west.  The first time Jules came up and glared at it,
and I backed it off and slewed past the bad spot -- Jules'
glaring probably helped too, as the telescope dared not defy
the Director.  The second time, I was 5 hr over in the east,
and when I auto-slewed back to the west the telescope stuck
at 4 hr east (and started heading for delta = -12  where I was
going -- I stopped it at 4.5 airmasses!).  I got out of it by 
leaning my back into the fork, hitting the slew button, and 
literally pushing the thing past the bad spot.  The telescope
also jumped or slipped numerous times while guiding, as it
did a few nights ago way over in the east.  It even did this
near the zenith. Curiously, later in the night when I was 
working west (up to nearly 5 h) I had no problems.  The 
temperature was also cooler by then, which may have had an 
effect.  

Jules and I watched the RA drive while I tried to slew past
the bad spot -- the motors and gears all turned apparently
normally, but the silver wheel (about 18 in diam) got stuck.
The set and track motions were also stuck -- it wasn't just 
slew.

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Submitted on 2001 Jun 29 [5:33:50]