MDM Trouble Report for 2009 May 30

Telescope: 2.4m
Observer(s): John Tobin and Hsin-Fang Chiang (U of M)
Instrument: TIFKAM

Problem(s) Encountered:
We are observing in a dither pattern, moving 15  every 2 minutes in
a 5 point pattern. When observing L43, hour angle of -2.5 and declination
of -15, the TCS would frequently not complete the move causing
the guider to not work well and drifting. The TCS fixes itself but
usually after 5 minutes of poor guiding. The TCS would
generally say one of the following:  Dec encoders not responding ,
 RA encoders not responding , or  RA or dec encoders not responding. 

The incomplete moves was less of a problem when we switched to a
northern source even though the hour angles were higher (started at
-5.0). But, the same problem still cropped up randomly.

Also, there seems to be some pattern noise associated with 
the detector readout. There is a wave pattern in the dark
images with about a 3 count amplitude. This pattern
varies over time so it if it is present in the science
frames it cannot be subtracted off, though with enough
combined images it will probably be filtered out.

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Submitted on 2009 May 30 [12:22:33]