Subject: DIS bias pattern

From: Gordon Richards

Submitted: Sat, 14 Sep 1996 13:48:52 -0500

Message number: 25 (previous: 24, next: 26 up: Index)

It came to my attention last week during an observing run that
the DIS only exhibits a bias pattern while mounted to the
telescope.  I see no discussion of this on this web page, and
was wondering if this is a well known fact?  I took some
unmounted biases for my run and they were some of the best bias
frames I've ever seen!  It seems obvious that the bias pattern
is produced as a result of the coupling to the telescope.  It
seems to me like this would be much easier to fix than an actual
problem with the camera electronics.  Is there some way that we
can isolate the camera from the telescope?  I should point out
that the DSC bias frames are also worse when mounted to the
telescope.  The difference is not quite as obvious for the DSC
as it is for DIS, but it is still there.

Gordon
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