MDM Trouble Report for 2009 May 2

Telescope: 2.4m
Observer(s): Cotto-Figueroa, Uckert, Statler (Ohio University)
Instrument: Direct/Echelle

Problem(s) Encountered:
Bob noticed in the afternoon that the CCD was warming up, probably
due to an incomplete fill in the morning. He refilled the dewar
and for the rest of the afternoon the CCD was cooling from about
-75 back down to -100. Horizontal banding in biases and data
frames reported previously persisted tonight. We first noticed
it when doing late afternoon biases; and since it was cloudy,
we tracked the behavior along with the CCD temperature. We'll
compile this data and send it to Bob separately. However, we saw
the system go through a long (~ 1 hour) temperature oscillation
as the heater kept overshooting the target temperature. During
these oscillations the heater voltage varied between 0% and about
80% voltage. It took several hours for this behavior to damp
out. Eventually the CCD settled to close to -100C with the
heater running at around 50% voltage.

------------------------------

Submitted on 2009 May 2 [5:45:59]