[vsnet-chat 3553] Re: NSV 14652 weirdities...

[Brian Skiff <bas@lowell.edu>]

     On the USNO-Flagstaff pixel-sever, the red/blue magnitudes choice is
simply for the screen plot that comes up, _not_ for the image data.  At the
moment, you get all available scans, sometimes 8-10 images in several
colors.
     Unless a star has an extremely red color, image brightness compared to
nearby field stars should be essentially the same on the POSS-I O plates
(i.e. the blue-light exposure) as on the POSS-II IIIa-J images since the
passband is nearly the same (slight extra red-end sensitivity on the IIIa-J
plates, but not much).  In the south, the POSS-I O (if covered) should be
the same as the ones with prefixes 'ao' or 'sb'.
     If you do see change in relative brightness amongst all the blue-
sensitive plates, then you immediately suspect variability.

\Brian

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