MDM Trouble Report for 2012 Apr 18

Telescope: 2.4m
Observer(s): Chris Miller & Ryan Hickox (Michigan & Dartmouth)
Instrument: OSMOS+R4K

Problem(s) Encountered:
Rotator stopped working on first attempt. Reboot of power/GUI did not work. But we found that a plastic zip tie had gotten in the way of one of the hard-limit detectors. Once we moved the tie, the rotator worked.
During the alignment of our second mask, we noticed that the shutter was in the FOV (it was not opening fully). We moved the telescope to zenith and took multiple short images. In those cases, the shutter opened only part way.
We could not fix the issue, and since our MOS targets are near the center of the FOV, we continued taking data.  During our second science exposure (1800s exposure taken around 10pm) showed no data. A following test image of the sky showed no data. We feared that the shutter was not opening at all. 
We noticed that humidity had peaked around the time the shutter was not working (although this may not be related). On the alignment of our third mask, the shutter was opening all the way again.

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Submitted on 2012 Apr 18 [4:38:30]