MDM Trouble Report for 2013 Sep 09

Telescope: 2.4m
Observer(s): Thorstensen (Dartmouth)
Instrument: Modspec + Templeton

Problem(s) Encountered:
I took a long series of MIS flat lamp exposures during the 
afternoon and into the evening -- 50 x 180 s -- and noticed 
that that the count rate went down very substantially, to 
maybe 60 percent of the  original,partway through the sequence.  
The fade was gradual.

To rule out some possible causes, I tried a Ne exposure 
similar to the ones I had used for setup
before the flat sequence, and it came in at the same exposure 
level as the ones taken before the flats.  

So it looks like the flat lamp itself faded, which is puzzling.
I thought incandescents tended to brighten before they blew 
out.    

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Submitted on 2013 Sep 10 [5:14:53]