GCN Circular 3744
E. Pavlenko, Yu. Efimov, A. Shlyapnikov, A. Baklanov(CrAO), A.Pozanenko (IKI), M. Ibrahimov (MAO) on behalf of larger GRB follow up collaboration report: We observed the error box of GRB050802 (Band et al., GCN 3734) with 2.6m Shain telescope (CrAO) on August 2 between (UT) 18:46 - 20:40. OT found by McGowan et al. (GCN 3739) is clearly detected. Preliminary VRI photometry is following: Mean time Exposure Filter Magnitude (UT) s 18:54 60 V 20.6 20:27 2x60 V 21.1 18:48 60 R 20.6 20:36 2x60 R 21.0 18:56 60 I 20.2 20:39 2x60 I 20.6 with a typical error of 0.1m. Comparing decay index of fading light curve in V between magnitudes obtained in UVOT observation (McGowan et al. GCN 3739) and our first observation in 18:54, and decay index obtained based on our observations we suggest that the break of OT light curve occurs between (UT) 19:00 - 20:40. Detailed analysis is underway. Finding chart of the OT in V band can be found in http://grb.rssi.ru/GRB050902. This message may be cited.