MDM Trouble Report for 2015 Mar 30

Telescope: 2.4m
Observer(s): Holoien, Danilet (Ohio State)
Instrument: OSMOS

Problem(s) Encountered:
Clouds prevented observing for most of the night, but we were able to get a couple of target during some brief windows. (UT 7:00~8:00 and UT 10:45:00 onward)

Had trouble with the dome encoders multiple times throughout the night, and eventually disabled the auto dome entirely. Some details:

- Periodically while tracking, the dome encoders would get lost. First the dome would be moving, but the  Dome Azimuth  field on the TCS would not be changing.
Then, if left long enough, the  Dome Encoders Not Responding  error message would appear.
The dome would then continue to rotate until both the Auto Dome switch was turned off AND the yellow button in the control room was disabled.
If we moved the dome manually to some azimuth and reset the encoders, we could turn the auto dome back on and it would work for a time, but eventually it got lost again.
The times the problem occurred and target coordinates are copied below.

- First occurrence was UT 3:45, early in the evening.
This happened while we were pointing near zenith, and we accidentally set the RA/Dec encoders to a value by the horizon.
The dome started moving to account for the new coordinates, but we then reset the RA/Dec encoders to the correct values, and the dome encoders stopped responding.
We reset the dome encoders, and it worked fine for a few hours.

- At UT 7:26:00, right after finally acquiring a target through the clouds and starting an exposure, the encoders stopped responding again.
This time, the auto dome switch on the TCS control panel did not stop the dome moving; only turning it off in the server room made a difference.
We reset the encoders to Az of 180, then turned the auto dome back on.

- At UT 7:40:00, shortly after restarting the dome, it lost the encoders again.
Target Alt/Az=72/170, RA/Dec=12:59:49.4/14:08:19. We left the auto dome off until the exposure completed.

- At UT 8:04:00, roughly 1 minute after restarting the auto dome, the encoders were lost again.
Target Alt/Az=72/188, RA/Dec=12:59:49.4/14:08:19. We decided to leave the auto dome off until the current target was finished.

- At UT 8:50:00 we moved to a new target and turned the auto dome back on. 5 minutes later (8:55:00) it stopped responding again.
We disabled the auto dome again.

After the fifth time the dome encoders stopped responding, we disabled the auto dome and left it off until the end of the night. 

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Submitted on 2015 Mar 31 [5:23:08]