MDM Trouble Report for 2011 Mar 27

Telescope: 1.3m
Observer(s): Terndrup, Karnath (NSF, OSU)
Instrument: CCD/Templeton

Problem(s) Encountered:
We have been having some minor trouble with the telescope tracking.
The main symptom is oscillations or position jumps in the N/S direction.

The problem does not directly affect our observing - unlike in previous,
runs where I more or less had to throw away a whole season's worth of
data.  We are taking rapid-cadence, unguided images of certain pre-CV
systems.  The observations consist of 15- or 20-second exposures, with
the readout area reduced to 512^2, yielding a cadence of about 28 sec.
We watch the images as they come in, and adjust the focus or the pointing
as needed during the observing sequence.

The telescope will sometimes oscillate N/S during an exposure by about
15-30 arcsec, or jump from 30 arcsec to about 1 minute of arc.  There are
rarer jumps in the E/W direction too.  These happen all night long, but
seem to be more common early in the night and/or when we recently
acquired an object.  They were more frequent on Saturday night, when it
was windier, but the jumps do not seem to be correlated with the
wind in any obvious way.  During the worst times, about 1/3 of the images
are affected.  This would be a serious problem with long exposures, as
the jumps exceed the range that the guider can correct.




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Submitted on 2011 Mar 28 [8:03:15]