TITLE: GCN CIRCULAR NUMBER: 12380 SUBJECT: GRB 110921A: optical observations in Mt. Terskol and Maidanak observatories DATE: 11/09/21 20:40:56 GMT FROM: Alexei Pozanenko at IKI, Moscow A. Pozanenko (IKI), M. Andreev, A. Sergeev (Terskol Branch of Institute of Astronomy), M. Ibrahimov (MAO) on behalf of larger GRB follow up collaboration report: We observed the field of the Swift GRB 110921A (Baumgartner et al., GCN 12373) with Zeiss-600 telescope of Mt. Terskol observatory and AZT-22 telescope of Maidanak observatory on Sep. 21. Several images were taken in both observatories in R filter. Within the enhanced XRT error box (Goad et al., GCN 12379) we do not detect the candidate of optical counterpart of GRB 110921A (Xin et al., GCN 12377). Preliminary photometry of a combined image (Zeiss-600) and a single image of AZT-22 is based on the nearby USNO B1.0 stars: UT Filter, Exposure, OT, Upper Limit (3 sigma) Telescope (mid) (s) Sep.21 16:50 R 1800 n/d 21.1 Zeiss-600 Sep.21 17:48 R 300 n/d 21.2 AZT-22 Since our photometry is somewhat deeper than photometry of the candidate (Xin et al., GCN 12377), we could suggest the candidate is a real afterglow of GRB 110921A.