MDM Trouble Report for 2008 Dec 8

Telescope: 1.3m
Observer(s): Joe Shields, George Eberts, Tom O'Grady (Ohio University)
Instrument: 4k

Problem(s) Encountered:
We encountered two problems.

1) The more worrisome one is that two of the four quadrants
for the 4k CCD do not appear to be producing usable data, i.e.
vertical streaked appearance with no evidence of detecting 
photons.  In normal display mode these are the two lower
quadrants.  Changing binning between 2x2 and 1x1 did not
solve the problem.  At least sometimes there is also 
indication of electronic pattern noise in the upper right 
quadrant.

2) We were unable to achieve a good focus with the R filter,
with all images showing elongation in stellar images in the 
horizontal (NS) direction - even when images sharpened up 
the result looked like tadpoles.  Total focus range explored 
was 750-840. This problem appeared to go away when we 
changed to V filter but we did not have time to optimize 
focus before being forced to close by rising humidity.

Images are available for inspection on disk: file prefix jn1
file numbers 1-21.  Images 1,2,4 are twilight sky R; 3,5 are
biases; 6-19 R band focus tests; 20-21 V band focus tests.
Image 7 is binned 1x1, all others 2x2.

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

Submitted on 2008 Dec 9 [4:33:33]