Re: stellar density as a function of magnitude

[<aah@nofs.navy.mil>]

The photometric question is one of the reasons behind
my suggestion that we not try to measure the faintest
stars on an image.  Not only do you have contaminating
fainter stars in your measurement aperture, but they
also contribute to the sky measurement.  It is much
easier to build a quality catalog from the brighter
stars, and you will have plenty of them anyway.
  For identifying blends, I'd rather use UCAC than
the other catalogs.  Remember, the POSS plates saturate
stars starting about V=14 so companions get difficult
to see.  The POSS-II scans are almost unusable near
the Bulge.  Also, proper motion is not insignificant in
the galactic plane fields; UCAC is a modern, CCD-based
catalog with about the same magnitude limits as are
reachable by TASS.
Arne