MDM Observatory 2.4m Telescope Observer's Report for 2007 Jul 20

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

Instrument: Modspec + Echelle CCD

Worked for 2.5 hours (off and on through the night)
Conditions were Mixed most of the night.
No equipment or software problems were encountered.

Seeing and Weather:
   Clouds from 9:20 until 3:30.
   Beg: Seeing 1. arcsec, Patchy Clouds, Winds Light & Variable
   Mid: Overcast, Winds Moderate
   End: Seeing 1.5 arcsec, Patchy Clouds, Winds Calm

Observing Summary:

The storms arrived notably late tonight, allowing for a rare
glimpse at the evening sky.  Started out pretty clear overhead,
with a storm far to the west over Ajo and another complex east of
Tucson, but the storm complex to the east soon spread our way
and forced us to close by about 9:20.  Fog rolled over the
observatory about 10, and by 11:15 we were in the middle of
a lightning storm, with moderate rain.  Several strikes came
within a few hundred yards of the observatory.  Restarted
computers around 2:30 after lightning was long past, and soon
had some clearing and rapidly falling humidity -- then managed
to actually get some observations through sizeable holes.  

Seeing was surprisingly good at the start, but deteriorated
abruptly as the storm approached.

The shutter behaved itself perfectly, including coming up 
correctly after the lightning shutdown.  The first test shot
did reveal condensation on the dewar window, so I had to flush
the window with dry nitrogen before getting those last few
observations of the night.

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Submitted on 2007 Jul 21 [5:02:57]