Re: [TASS] Flat fielding

[Glenn Gombert <gleng@INFINET.COM>]

>But I solemnly warn you. The Mk III flat fielding sort of
>works because, and only because, drift scan is easy. The
>Mk IV is worse by a factor of several in DEC times a factor
>of two thousand and thirty two in RA. Woe to those who
>build their sacred star lists on a foundation of wispy
>cloud.
>
   The ingenious method that Mike G. came up with in his "FlatComp" program
actually compensates for a "multitude of sins" when it comes to being able
to Flat-Field wide-field ccd images from light polluted urban locations.
Mike has not received suitable credit on the list for using Tycho stars
present in each image to enhance the photomertic accuracy of our Mark III
measurements.

        Arne and some of the other Mark IV sites will probably be able to do quite
well with "normal" flat-fielding procedures but from light polluted sky’s
in the Midwest we will have to use a great deal of creativity to improve
the quality of our measurements with the Mark IV systems....

Glenn G.