RE: Flat Compensation Consistency

["Gutzwiller, Michael" <mgutzwiller@lanvision.com>]

Night 371 may look different because it is actually the first night of
saved data from my system (mid October 1996) and I was still adjusting
the system so the true flat may be legitimately different from the other
days implying a slightly different compensation.

Camera 2 was partially obscured at this time and actually had
adjustments one magnitude different from the other cameras which may
have given rise to a particularly poor original flat.

	-----Original Message-----
	From:	aah@nofs.navy.mil [SMTP:aah@nofs.navy.mil]
	Sent:	Thursday, May 28, 1998 12:09 AM
	To:	tass@wwa.com
	Subject:	Re: Flat Compensation Consistency

	Mike,
	  Your data looks great and is definitely encouraging.  Any idea
	why night 371 is different than the others (fewer stars?
Different
	RA range so you pick up a different set of Tycho stars?)?
	  I'm surprised camera2 is so different.  My gut feeling would
	be that all three cameras should have about the same fit, since
	the compensation is supposed to be due to things like gradients
	in the sky (and all 3 cameras will eventually image the same sky
	regions).  All I can think of is some scattered light getting
	into that camera that is not present in the other 2 cameras.
	Arne