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Re: flatfields



aah@nofs.navy.mil wrote:
>   We've combined data from several TASS sites, with cameras pointed at
> quite different declinations, and the data agree with the 0.05mag sigma.
> This would be impossible if the slope you propose is true.  On the other
> hand, Michael R. had trouble on his one good night with the Vermont triplet
> with a slope of comparable size.  These hints at huge gradients, at least
> on some of the frames, are very disturbing.
> 

This worried me a little too until I realized that the magnitude
variations we have been using are from the differental magnitudes list. 
Doing a differential magnitude setting would obscure some of the slopes
I have been seeing since they would have been averaged out to a greater
or lesser degree depending on the declination distribution of the
comparison stars.


Mike G.