MDM Trouble Report for 2018 Feb 07

Telescope: 2.4m
Observer(s): Douglas, Weaver, Carmichael (Columbia)
Instrument: OSMOS/R

Problem(s) Encountered:
The guide probe couldn't hold its position at all the entire 
night. The probe couldn't seem to find the new guide star if we 
moved it without sending it to origin first --- and when we sent
it to origin, it always stopped moving with the green numbers 
saying 0 and 0, but at the bottom left of the xmis window it would
say  Ready PROBE X=### Y=0  where ###>0. We would have to send
it to origin a second time, and then out to the new guide star. 
It still didn't always land in the correct spot in these cases. 
We also got the  warning, not at x cw limit  error 4-5 times and
had to power-cycle the MIS in those cases. 

Guider residuals have also been higher than in past nights; we've
had aggressiveness=4.5 or 5 for the entire run, but tonight we had
to lower it to 4. This still didn't solve the entire issue, but
made us think that perhaps the guide probe is drifting during 
observations. This would explain the lowered flux, if the star is 
being slowly pulled out of the slit. We haven't tested that with
sky images yet, though. 

A few more notes on the lowered flux - compared to two nights
ago (since we had counts issues last night too), sky images
have ~3x fewer counts tonight. The reduction in flux for the spectra
is harder to judge because we increased the exposure times, 
but even more than doubling the exposure time
still led to fewer counts in some cases. The mirror cover was
fully open, the dome was not occulting the telescope, we
re-ran the filter commands to make sure they were in the right
place, and the dark hatch was open. So as far as we can tell 
there wasn't an obstruction in the light path that we could 
deal with.

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Submitted on 2018 Feb 8 [6:23:23]