TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3174 SUBJECT: GRB050401: Maidanak optical observation DATE: 05/04/02 22:10:22 GMT FROM: Alexei Pozanenko at IKI, Moscow B. Kahharov, M. Ibrahimov, D. Sharapov (MAO), A.Pozanenko (IKI), V.Rumyantsev (CrAO), G.Beskin (SAO) report: We observed the afterglow (McNaught and Price, GCN 3163; Rykoff et al., GCN 3165) of the Swift GRB050401 (Angelini et al., GCN 3161; Barbier et al., GCN 3162) with 1.5m telescope of Maidanak Astronomical Observatory (MAO), Uzbekistan under good weather conditions (seeing is 1.0 arcsec). Preliminary R-photometry against of USNO-B1.0 Catalog is following: Mean time Exposure Mag. (UT) (s) Apr. 1.988 8x300 22.2 +/- 0.2 This message may be cited.