MDM Observatory 2.4m Telescope Observing Report for 2021 Jun 20

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

Instrument: OSMOS

Worked for 8 hours (all night)
Conditions were Non-Photometric most of the night.
No equipment or software problems were encountered.

Seeing and Weather:
   High Humidity from 3 AM until end.
   Beg: Seeing 1.5 arcsec, Clear, Winds Moderate
   Mid: Seeing 1.5 arcsec, Patchy Clouds, Winds Calm
   End: Seeing 2.5 arcsec, Clear, Winds Light & Variable

Observing Summary:

Mostly clear night, but seeing not as good or consistent as
previous night.  Also, a bank of clouds covered part of the sky
around midnight, and then dissipated.  The weird part was that 
at the end of the night, the humidity, which has been negligible
all week, jumped up to the low 70s, which was enough to start
condensation on the 4k dewar. I didn't notice this until twilight
had begun, so I simply closed up at that point rather than trying
to flush the dewar window with dry nitrogen.  I'm pretty sure I
was also smelling forest fire smoke outside in the last hour
or two of the night, but I expect it was from a long distance
away.  Equipment all worked fine.

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Submitted on 2021 Jun 21 [4:12:22]