TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  1197
SUBJECT: GRB011211, BVRI field photometry
DATE:    01/12/13 17:22:44 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 that is approximately centered on
the position of the candiate optical transient reported
by Grav et al. (GCN 1191) with the USNOFS 1.0-m telescope
on one photometric (but poor seeing) night.  Stars brighter than
V=13.5 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/grb011211.dat
The current photometry has a potential external zero-point
error of about two percent.  The astrometry in this file
is based on linear plate solutions with respect to USNO-A2.0.
The internal errors are less than 100mas.

In particular, the comparison star U0675_11427359 that was
used to calibrate their field can be found in the .dat file
with the following magnitudes:
  B = 18.65  V = 18.11  R = 17.76  I = 17.42
with estimated photometric errors of about 4 percent, including
the zeropoint errors quoted above.

Further calibration of this field will be performed when
weather conditions improve.