MDM Observatory 2.4m Telescope Observing Report for 2019 Sep 04

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

Instrument: Modspec/B

Worked for 6 hours (last half of the night)
Conditions were Mixed most of the night.
No equipment or software problems were encountered.

Seeing and Weather:
   Clouds from start until 23:30.
   Beg: Overcast, Winds Moderate
   Mid: Seeing 1.4 arcsec, Clear, Winds Light & Variable
   End: Seeing 1.4 arcsec, Clear, Winds Light & Variable

Observing Summary:

Definitively cloudy until around 11:30 -- stratus-like overcast 
from a big convection cell.  This gradually moved off to the 
north and then disappeared rather quickly.  After that is 
was mostly clear with decent seeing, with a few clouds here
and there.  

The telescope jumped a couple of times, but fewer than last
night - for one thing, I wasn't open as long.  

While it was cloudy I ran a test determining the OSMOS' camfoc
using emission line widths, and came up with a number rather
lower than nominal -- for the 1.2 arcsec slit and blue grism
I got around 4700 microns at a bench temperature of 23 
degrees.  This was quite a bit lower than what I'd been 
using.  When I got on sky, the stars were out of focus, probably
due to the sizable change in camera focus.  

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Submitted on 2019 Sep 5 [6:04:38]