MDM Trouble Report for 2015 Apr 27

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

Problem(s) Encountered:
Two comparison exposures early in the night came out blank - like
biases - despite definitely having light on the slit (I could
see it in the slit-viewer).  This suggests the shutter didn't
open.  I checked that I hadn't forgotten to select the 
Open Shutter box on the Owl gui; that didn't appear to 
be the problem. We exercised the shutter with the Quick 
Actions icon that controls it, and could hear it operating.
Then, weirdly, the problem didn't recur, so it's probably best
to let it be for now.

When trying to account for mediocre seeing I looked at the 
mirror A/c temperature graph, and the mirror cooling appeared
to have stopped working early the previous day.  It was
cooler than ambient so this didn't cause the problem.  The
lack of cooling might
have caused by humidity, or something, but it seemed nice
and dry.  Please verify that the mirror AC is cooling OK.

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Submitted on 2015 Apr 28 [5:37:14]