Re: Preliminary Mark III Data Reprocessing Results

[hjohnson@pluto.njcc.com (Herbert R Johnson)]

On Thu, 06 Aug 1998 04:19:51 -0400, Glenn Gombert <gleng@infinet.com> wrote:
*>Hello,
*>
*>        I have been experimenting with using Mike G's new "FlatComp" program
*>to reprocess 14 nights of Mark III data taken last year in Dayton and the
*>initial results appear _very_ encouraging. The FlatComp program is used to
*>correct background variation in Mark III starlists due to flatfielding
*>errors, sky backgound gradients, etc that limit the accuracy of the
*>photometry that we have been able to achieve in Mark III data collection,
*>reduction and processing.

I'm curious as to what you see as field errors that are attributable
to the optics. Is there a way to produce an image (or data array)
that represents these variations in the field? I'm thinking of something
like the skyfield flat image I took with the Orion lens as per my
Web page report (in my Astronomy section).

More generally, and a related but seperate issue, can
you produce a "correction image" or some kind of measures that simply
represents variations in the background for a given TASS run?
A low pass filter with a dark current cutoff would do about as
much I suspect, but similar data may well "fall out" of the program
you are using. The bottom line is to get some useful comments about
seeing quality criteria or about any Mark III camera attributes
that contribute to excessive (or avoidable) variations in the image data.

Herb Johnson

Herbert R. Johnson              http://pluto.njcc.com/~hjohnson
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