GCN Circular 1301
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 Bloom et al. (GCN 1296) with the USNOFS 1.0-m telescope on one marginally photometric 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/grb020322.dat The conditions were basically clear, but with weather maps indicating passing clouds over the northern horizon in the direction of the GRB field. There is a slight possibility that the photometry has larger than the expected 0.02mag external error, but all tests (such as color consistency) seem reasonable. 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 USNO-A2.0 star at 18:00:58.03, +81:06:08.3 that was used to calibrate their field can be found in the .dat file with the following magnitudes: B = 19.42 V = 18.12 R = 17.30 I = 16.59 with estimated photometric errors of about 2 percent, including the known zeropoint errors quoted above. Further calibration of this field will be performed when weather conditions improve and moonlight decreases.