TITLE: GCN GRB OBSERVATION REPORT NUMBER: 691 SUBJECT: GRB000528, optical observations at ESO DATE: 00/06/07 16:46:29 GMT FROM: Nicola Masetti at ITeSRE,CNR,Bologna E. Palazzi, N. Masetti, E. Pian, F. Frontera (ITESRE, CNR, Bologna), A.J. Castro-Tirado (LAEFF, IAA), J. Hjorth (Univ. of Copenhagen), P.M. Vreeswijk, E.P.J. van den Heuvel (Univ. of Amsterdam), J. Greiner (AIP), P. Francois, J. Brewer and O. Hainaut (ESO) and L. Piro (IAS, CNR, Rome), on behalf of a larger collaboration, report: "We obtained optical R-band images of the field of GRB000528 (BeppoSAX Mails #00/10, #00/11) on 2000 May 29.10, May 29.96 and June 4.02 UT (i.e. 18 hr, 38 hr and 160 hr after the GRB, respectively) with the 1.54-meter Danish telescope (plus DFOSC) at ESO - La Silla (Chile). These images contain the BeppoSAX WFC error box of this GRB (GCNs #677, #681) and the two MECS sources reported in GCN #683. Seeing was ~1.3 arcsec on the three epochs. Exposure times were 15 min for the first observation, 10 min for the second and 45 min for the third. Photometric calibration was performed using standard stars in the Landolt field SA107 (Landolt 1992, AJ 104, 340). The comparison between pairs of images does not reveal any object with significant brightness variation down to a 3-sigma limiting magnitude of R ~ 23.3.". This message can be cited.