MDM Trouble Report for 2005 Jun 29

Telescope: 2.4m
Observer(s): J. Thorstensen, H. Sheets (Dartmouth)
Instrument: Modspec + echelle CCD

Problem(s) Encountered:
This problem occurred the night of June 28, but we didn't 
appreciate its seriousness at the time; I'm documenting it
here.

We noticed a sudden drop in the flux of a star partway through
the night, and tried to understand it, but didn't try quite 
hard enough as it turned out.  The shutter had broken -- only
half of it was opening!! This was the replacement shutter which
Bob had just installed, a part of the mechanism simply snapped.
We did figure it out on looking more closely at the data the
next day.  When Bob checked it out he found that the Uniblitz
control box was not giving sufficient voltage, which seems to 
have explained the earlier shutter problem we were having.  So
we've just had very bad luck with shutters this run ... 

We lost almost no time but for most of the night we were in
effect observing with 1/2 the aperture or less, depending on 
where we put the star along the slit.  We woulda, shoulda, 
coulda diagnosed it on the spot by looking at the 2-d spectra,
but we're always working on stars and extracting the 1-d 
spectra.  Moral: look at 2-d spectra from time to time.

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Submitted on 2005 Jun 30 [5:17:39]