TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3004 SUBJECT: GRB 050128 Optical observation with REM DATE: 05/02/01 19:14:52 GMT FROM: Angelo Antonelli at Obs. Astro. di Roma A. Melandri, E. Palazzi, L. A. Antonelli, S. Covino, P. D'Avanzo, G. Tagliaferri, G. Chincarini, F. M. Zerbi, G. Tosti, A. Monfardini, N. Masetti, L. Nicastro, G. Cutispoto, E. Molinari, M. Rodono' and F. Vitali on behalf of the REM/ROSS team, report: "We imaged the field of GRB050128 (Antonelli, et al., GCN 2991) with the 60cm REM robotic telescope located in La Silla (Chile). Optical observations were carried out in V, R, I filters starting on 2005 Jan 28, at 7:10 UT, and ending at 9:45 UT (approximately 3 hours after the burst) . Observations have been partly affected by the presence of the bright Moon close to the field, so only frames with short exposure time can be used. The field was imaged in each filter for a total exposure time of 50s. No new sources are detected within the XRT error circle (Antonelli et al. GCN 2991) down to a limiting magnitude of V >18.2, R >18.2 and I >17.9. The source noted in the H band (Covino, et al., GCN 2999) at RA= 14:38:18.16, DEC=-34:45:44.7 (J2000) at about 13 arcsec far from the XRT position is not visible in the optical bands. We derive a 3-sigma upper limit of R > 18.2 at the position of this source. Further optical-infrared observations with REM are planned to look for any variability. This message can be cited."