TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  1424
SUBJECT: GRB020604, BVRcIc field photometry
DATE:    02/06/11 20:39:02 GMT
FROM:    Arne A. Henden at USNO/USRA  <aah@nofs.navy.mil>

A. Henden (USRA/USNO) reports on behalf of the USNO GRB team:

We have acquired BVRcIc all-sky photometry for
an 11x11 arcmin field centered at the coordinates
for the IPN burst GRB020604 (Hurley et al., GCN 1417)
with the USNOFS 1.0-m telescope on one photometric night.  Stars
brighter than V=14.0 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/grb020604.dat
The astrometry in this file is based on linear plate solutions
with respect to UCAC2.  The external errors are less than 100mas.
The photometry has potential zeropoint error of about 0.03mag.
This is a fairly crowded field, so the automated reduction pipeline
will have problems on blended objects.

Editorial note: the NOFS 1.0m has a hard declination limit of
-31 degrees.  GRB020604 is as far south as we will normally
observe, and even then, our potential zeropoint error is
quite large due to the high airmass.  GRB020405, at -31 dec,
was just outside our declination limit.  Therefore, any time
a burst is localized south of -30, you will not see
field photometry posted from NOFS.