From stiening@cannon.astro.umass.edu Thu May 16 12:06:18 2002
Date: Tue, 4 Dec 2001 14:08:09 +0000 (GMT)
From: Rae F. Stiening <stiening@cannon.astro.umass.edu>
To: Roc Cutri <roc@ipac.caltech.edu>
Subject: Re:  USNOA (fwd)



---------- Forwarded message ----------
Date: Tue, 4 Dec 2001 07:02:44 -0700
From: dgm@nofs.navy.mil
To: stiening@cannon.astro.umass.edu
Subject: Re:  USNOA

For USNO-A entries wherein we quoted Tycho for positions as red magnitude,
the blue magnitude field was intentionally set to zero, as was the Q flag
(quality) and the 3-digit POSS field number.  This was to allow users to
understand that these entries were included for the sake of completeness,
and that the data came from the Tycho catalog.  If it is not grossly
inconvenient, you might leave your b_m_opt as nulls.  For the casual
user, these would read as zero which is more or less the same as in USNO-A,
and for those who can read the documentation, they can understand that
these entries are (still) not from PMM but from Tycho.

-Dave