MDM Trouble Report for 2012 Apr 22

Telescope: 2.4m
Observer(s): Yan, Brown, Runge, Musin (University of Missouri-Columbia)
Instrument: OSMOS+R4K

Problem(s) Encountered:
We encountered a series of problems:

1) The TCSlink was not up at the beginning, and it took us a while
to realize that this was causing problem. While there was a note
posted on the wall behind Hiltner's monitor, we didn't notice that
and had to call Bob to get the solution. Lost about 30-40min.

2) Focusing was also a problem. It took us more than 1.5 hours to
tune the focus, but the end result was still not satisfactory -
the star images were still a bit elongated in SE-NW direction. We
even tried to adjust the ColFocus value, but without any success
(it was set back to the default 2300um). We decided that the best
CamFocus value was 5830um.

3) Auto guiding had problems. First of all,  Move Guider Probe 
didn't seem to work well -- it had to be clicked multiple times,
and it took many minutes until the guider actually moved. Quit
JSkyCalc24mGS and relaunch didn't improve the situation. Second,
the guider was badly out of focus, and after checking the old
night reports we realized that it had to be manually adjusted.
Third, the  Calibrate  step often failed -- about 50% of the time
there were no red lines appeared on the chosen star indicating
the movements, and we had to start over every time. In a number
of times the  Calibrate  step went through, but when clicking on
 track , the star disappeared from the auto guider image. Forth,
it was found that the third problem could be related to a strange
behavior of the frequency of the camera -- while it is supposed
to stay at 1MHz, every time it jumped to 2.8MHz by itself, and
whenever this happened, the  Calibrate  step would fail. Our
workaround was to set it back to 1MHz every time. Fifth, the
guider probe position was off by a large amount towards the
end of the night. We noticed that there was some offset at the
beginning of the night (the selected guide star was not even
close to the central region of the  CCD Image  window), however
it got worse and worse towards the end of the night -- it finally
got to the northern edge of the window and any follow-up steps
were impossible. We had to manually offset the guider probe by
faking the guide star position in X direction (adding 200-300
units to the shown position) to move the probe in place.

4) While taking the morning twilight sky flat, we noticed that
the edge of roi1k saturated badly while the central region was
still of very low value (only a few thousand ADU). Switching to
roi4k didn't have this problem, however we lost most of the
time due to the fact that we were not able to use roi1k to test
the sky brightness.

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Submitted on 2012 Apr 22 [11:00:02]