TITLE: GCN CIRCULAR NUMBER: 6482 SUBJECT: GRB070521: optical observation DATE: 07/06/02 16:32:24 GMT FROM: Vasilij Rumjantsev at CrAO V. Rumyantsev (CrAO), V. Biryukov (CrAO, SAI MSU), A. Pozanenko (IKI) on behalf of larger GRB follow up collaboration report: We observed error box of GRB070521 (Guidorzi et al., GCN 6431) with 1-m Zeiss (Simeiz) telescope of CrAO in R-band on May 21 between (UT) 20:38 and 21:00. No object is found in a refined XRT error box (Guidorzi et al., GCN 6452). Limiting magnitude of combined a image is based on USNO A2.0: Mid time (UT), Exposure, R_Lim (3sigma), Telescope, Seeing May 21.868 20x60 22.4 1-m Ziess 2.3" This message may be cited. [GCN OPS NOTE(02jun07): The binary attachment was removed as well as the diagnostics from MIMEDefang reacting to that binary.]