TITLE: GCN CIRCULAR NUMBER: 13912 SUBJECT: GRB 121011A: optical observations DATE: 12/10/27 23:02:08 GMT FROM: Alina Volnova at SAI MSU A. Volnova (SAI MSU, IKI), Moskvitin (SAO RAS), V. Rumyantsev (CrAO), A. Pozanenko (IKI) We observed the field of the Swift GRB 121011A (Racusin et al., GCN 13845) with ZTSh telescope of CrAO on Oct. 15 between (UT) 17:36 and 18:54 under good weather condition with mean seeing of about 1.5 arcsec. We took 70 frames with exposure of 60 seconds in filter R. In a stacked image we do not detect any source within enhanced XRT error circle (Evans et al., GCN 13850). We also observed the field of this GRB with Zeiss-1000 telescope of SAO RAS on Oct. 17 between (UT) 17:45 and 18:38 under good weather conditions with mean seeing of about 2.4 arcsec. We took 12 frames with exposure of 200 seconds. On a stacked image we do not detect any source either. The photometry based on a USNO-B1 star #1310-0279773 (R1 = 17.84; same as calibration in Fynbo et al., GCN Circ. 13856; Malesani et al., GCN 13853) is following: T0+ Filter, Exposure, OT, UL (3 sigma), Telescope (days) (s) 4.292 R 70x60 n/d 23.5 ZTSh 6.294 R 12x200 n/d 22.3 Zeiss-1000