MDM Observatory 2.4m Telescope Observing Report for 2017 Mar 07

Observer(s): Paust
Institution(s): Dartmouth

Instrument: OSMOS/4K

Worked for 11 hours (all night)
Conditions were Non-Photometric most of the night.
No equipment or software problems were encountered.

Seeing and Weather:
   Beg: Seeing .9 arcsec, Clear, Winds Calm
   Mid: Seeing 1 arcsec, Cirrus, Winds Calm
   End: Seeing 1.2 arcsec, Cirrus, Winds Calm

Observing Summary:

Apparently my complaints yesterday about seeing were answered.  After finishing twilight flats, I was trying to focus and it was miserable.  Normally, you can use the astigmatism to judge focus, but I was getting weird psfs where the inner isophots tilted one way and the outer ones tilted the other way.   After more frustration, I started imagining that the outer isophots maybe were a little bit triangular (and the airbags were clicking a lot).  I went and checked the airbag computer and the hard points were differing from each other by a full pound.  So I followed the lightning shutdown instructions to deflate the airbags and fill them back up.  Try focussing again and, wham, everything is glorious.  In the first part of the night, I could get sub-arcsecond images even with ~minute exposures.  

It probably also helps that the wind was dead flat at the begining of the night.

Some thin high cirrus rolled in at about 11 pm and my image quality started to go down, mainly because the guider seems to have some trouble at lower declinations (I was at about +15).  The guiding in dec was nearly zero, but the telescope and guider seemed to be fighting in RA.  A lot of images ended up being blurred slightly in RA, but seeing was still in the 1.1 to 1.2 arcsecond range. 


Long nights this time of year.  I'm looking forward to going to sleep.

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Submitted on 2017 Mar 8 [7:01:56]