MDM Trouble Report for 2004 May 12

Telescope: 2.4m
Observer(s): Schneider (Kapteyn Institute)
Instrument: 8K

Problem(s) Encountered:
I didn't forget to hook the nitrogenhose on to the camera in 
the early evening! But I must admit I didn't wait untill it 
started pouring out of the camera, what I was told was the only 
way to be sure it was full, although I let it on for at least 
10 minutes which I thought was enough... The evening started 
with horrible skyflats, the CCD looked awfull, that probably 
should have been my first clue but I didn't get it untill 
around midnight when the backgroundcounts had risen to 
ridiculous heights (over 10 000). When I went into the dome to 
see what was going on, the vacuum-value had risen to 30.8! I 
shut the CCD down and hooked up the nitrogenhose on and happily 
enough the number started dropping again. I let the nitrogen on 
untill now I was really sure the camera was full because the 
nitrogen was pouring out. The value had dropped to its normal 
0.3. For an hour or so herafter I took biases to see whether the 
CCD had cooled down enough to continue. When it did, it was 
around 4 a.m. by then, I could do just one of my targets before 
sunrise. I didn't encounter any more problems during that last 
hour. The vacuumvalue stayed at 0.3. In the morning I hooked 
up the nitrogen again, just to be sure it got properly cooled 
now.

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Submitted on 2004 May 14 [5:08:17]