TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5184 SUBJECT: GRB060502b: optical observations DATE: 06/05/29 10:02:37 GMT FROM: Alexei Pozanenko at IKI, Moscow V.Rumyantsev (CrAO), R. Karimov (MAO), R. Salyamov (MAO), E. Pavlenko (CrAO), Yu. Efimov (CrAO), A. Pozanenko (IKI), M. Ibrahimov (MAO) on behalf of larger GRB follow up collaboration report: We observed the location of Swift short GRB060502B (Troja et al., GCNs 5055, 5059, 5063, 5093) in the R band with 1.5m telescope of Maidanak Astronomical Observatory (MAO) starting on May 02 22:43 (UT) (5.3 hours after the trigger) and Shajn 2.6m telescope of CrAO between May 03 (UT) 01:27 - 02:41 (8.6 hours after the trigger). Totally we obtained 6 images of 180 sec exposure with mean seeing ~0.95" in Maidanak 1.5m and 39 images of 60 sec exposure in CrAO observatory (seeing ~3"). In combined images we detect G1 galaxy mentioned by Berger et al. (GCN 5071) and Halpern et al. (GCN 5072) and do not detect S2 source (Price et al. GCN 5077). A photometry of G1 and S1 sources is based on USNO B1.0 star R=17.5 mag (USNO-B1 426-035230 RA, Dec = 278.92572,52.61611): Mid time Telescope Exp. G1 S1 Limiting (UT) sec mag mag mag May 02.954 MAO 1.5m 6È180 ~24.2 21.40 +/-0.10 23.6 May 03.086 CrAO 2.6m 39x60 23.7 +/-0.3 21.65 +/-0.05 24.1 Our brightness estimation of G1 is consistent with brightness estimations obtained in MDM 1.3 (T0+15 h) R~23.9 (Halpern et al. GCN5072) and in Gemini North (T0+17 h) R~23.8 (Price et al. GCN5077). The combined images can be found in http://grb.rssi.ru/GRB060502b This message may be cited.