[vsnet-newvar 1481] (fwd) Re: Probable new faint variable star in Scorpius

[Taichi Kato <tkato@kusastro.kyoto-u.ac.jp>]

From: Brian Skiff <Brian.Skiff@lowell.edu>
Date: Sun, 16 Jun 2002 22:30:17 -0700 (MST)

     Be careful and generally skeptical about interpreting plate-scan
catalogues in such crowded regions.  The GSC-2.2 detection is flagged
unsurprisingly as '3', meaning a clump, so the red magnitude of 16.05 is
greatly vitiated by the crowding.  It is more likely some combination of
two or more stars within a few arcsec radius.  It also skews the position,
since it is something like a weighted photo-center for the blob of stars.
     YOu can make a better assessment of variability (but not necessarily
definitve) by requesting a complete set of cutouts from all available 
plates at the USNO-Flagstaff "pixel server":

http://vsnet.nofs.navy.mil/data/FchPix/cfra.html

Because of the level of detail, get images only 2'x2' or 3'x3' in
area, not the default 10' field.  Get the coordinate grid overlain
also, so you can get good positions to search on in catalogues in VizieR.

>>  At this place on DSS1 (blue)....

     In this field, the DSS1 scan is from a short-exposure V plate.
The magnitude limit is about 16 or so.

\Brian

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