TITLE: GCN GRB OBSERVATION REPORT NUMBER: 608 SUBJECT: GRB 000307, BVRI Field Photometry DATE: 00/03/10 19:57:41 GMT FROM: Arne A. Henden at USNO/USRA A. Henden (USRA/USNO) reports on behalf of the USNO GRB team: We have acquired preliminary BVRcIc all-sky photometry for the field of GRB000307 with the USNOFS 1.0-m telescope on one photometric night. This 11x11arcmin field covers the IPN error box and extends a little fainter than V=20. All stars brighter than V=14 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/grb000307.dat This file will be updated if an optical transient is discovered. 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.