TITLE: GCN GRB OBSERVATION REPORT NUMBER: 583 SUBJECT: GRB 000301C, UBVRI field photometry DATE: 00/03/05 00:04:18 GMT FROM: Arne A. Henden at USNO/USRA A. Henden (USRA/USNO) reports on behalf of the USNO GRB team: We have acquired preliminary UBVRcIc all-sky photometry for the field of GRB000301C with the USNOFS 1.0-m telescope on one photometric night. This 11x11arcmin field covers the IPN error box, contains the proposed optical counterpart, and extends fainter than R=20. The file includes the Garnavich, et. al. (GCN 573) R-band comparison stars with similar magnitudes within errors. We have placed the photometric data on our anonymous ftp site: ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb000301c.dat This file will be updated as soon as the weather improves. The current photometry has a potential external zero-point error of about two percent. Negative errors are Poisson only; positive errors are standard deviation of two or more measures. The astrometry in this file is based on linear plate solutions with respect to USNO-A2.0. The internal errors are less than 100mas.