MDM Trouble Report for 2001 Oct 15

Telescope: 2.4m
Observer(s): Jacob Noel-Storr (Columbia)
Instrument: CCDS

Problem(s) Encountered:
Before the start of the night CCDS was producing 'hot' frames,
at about 6pm (1/2 hour after filling the dewar) the temp. was
at -63 degrees. We called Bob to check for known issues, he 
suggested that we continue refilling, which did (eventually) 
lower the temperature to the -104.9 degrees desired. (About
1 hour of observing time lost).

At 11:30pm after the first series of observations we noticed
that the detector had started to warm up again (now at -83
degrees), and was again producing hot frames. We filled the
dewar again - however the temperature seemed to continue to
rise. After about an hour of trying this, the temperature seemed
to start falling again. We moved to a new target and started
observations - however the chip started heating up again so
these data were lost. Now at -77 degrees we added more N2 to the
dewar, and the temperature fell back to -104.9 after about 1 more
hour. (total loss about 3 hours).

At the end of the night the detector again heated up (to -90 
degrees). We refilled, though this seemed to have no immediate
effect. About the last hour of observing was lost. I will refill
again before going to bed this morning to try and keep the temp.
down.

Each time we filled during the night we waited for several
minutes of 'overflow' to ensure that we had completely filled
the dewar each time.

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

Submitted on 2001 Oct 15 [5:53:00]