GCN Circular 3454

A. Henden (AAVSO/USNO) reports on behalf of the USNO GRB Team:

We have acquired BVRcIc all-sky photometry for 11x11arcmin
fields centered on the coordinates of recent GRB localizations
with the USNOFS 1.0-m telescope on one photometric night
but with bright moonlight.  Stars brighter than V=12.0
are saturated and should be used with care.  We have placed
the photometric data on our anonymous ftp site:

ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050319.dat
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050401.dat
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050408.dat
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050416.dat
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050502a.dat
ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050509b.dat

The astrometry in these files is based on linear plate solutions
with respect to UCAC2.  The external errors are less than 100mas.
The estimated external photometric error is about 0.03mag.

Since these bursts had identified optical afterglows, we expect
to improve the photometric calibration on subsequent nights.
As always, you should check the dates on the .dat file prior to
final publication to get the latest photometry.  There is
a README file on the ftp directory to give you information
about the procedures used to calibrate these fields.