MDM Trouble Report for 2017 Feb 20

Telescope: 2.4m
Observer(s): Douglas, Nunez, Cortes (Columbia Unviersity)
Instrument: ModSpec/Echelle

Problem(s) Encountered:
This is a known problem, but caused us some anxiety tonight anyway. 
Eric had showed us the issue where a short in a ribbon 
cable on the mirror A/C computer caused the readings to go 
haywire, but it had mostly been behaving. However, tonight it 
was all over the place - if left alone, the temperatures would 
usually slowly creep up to believable but likely incorrect temps. 
However sometimes they read out whacky things like 30 or 3000 
degrees. Poking the ribbon cable a bit would sometimes bring 
the readings back down, but overall it made us skeptical of the
mirror temp readings. 

This led us to stay closed when we possibly could have opened 
once the humidity dropped (this might be of less concern on 
nights where the primary starts above the dewpoint, but since it
started below the dewpoint, we wanted to be sure before we opened). 
As noted in the observing report, on the advice of Rob Fesen, 
we eventually opened the mirror and checked for condensation 
before observing for a few hours. 

Also, the dome lost counts going in the CCW direction near the end 
of the night. We only noticed it when the dome was going home,
and it landed at 15 degrees instead of 320. It's possible this was 
responsible for our low counts and trouble guiding on our last 
couple targets, but we didn't check on it then. 

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Submitted on 2017 Feb 21 [5:46:12]