TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5186 SUBJECT: GRB 060526: RTT150 optical observations DATE: 06/05/30 05:05:45 GMT FROM: Rodion Burenin at IKI, Moscow I. Khamitov (TUG), I. Bikmaev, N. Sakhibullin (KSU/AST), Z. Aslan (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.), R. Burenin, M. Pavlinsky, R. Sunyaev (IKI) report: We observed the optical counterpart of GRB060526 (Campana et al. GCN 5162; French & Jelinek GCN 5165; Rykoff et al. GCN 5166) with Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe,TUBITAK National Observatory, Turkey), starting at May. 29, 18:44UT, i.e. ~74.26 hours after the burst. A series of frames were taken. The afterglow is detected in Rc band and marginally in V. We estimate the following Rc magnitudes for the OT: t-t0 m_R err 76.03 22.19 0.07 78.13 22.31 0.07 80.40 22.45 0.12 These points lie approximately on the extrapolation of the first day power law decay (e.g., Khamitov et al., GCN 5173). Our Rc lightcurve can be found at: http://hea.iki.rssi.ru/grb/060526/lc_0529.jpg This message may be cited.