TITLE: GCN CIRCULAR NUMBER: 22169 SUBJECT: GRB 171123A: TShAO optical upper limit DATE: 17/11/24 23:05:11 GMT FROM: Alexei Pozanenko at IKI, Moscow A. Volnova (IKI), A. Kusakin (Fesenkov Astrophysical Institute), I. Reva (Fesenkov Astrophysical Institute), E. Mazaeva (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of the Swift GRB 171123A (Evans et al., GCN 22148) with Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory starting on Nov., 23 (UT) 23:31:56. We took several images in R-filter. Within enhanced XRT error circle (Goad et al., GCN 22150) we do not detect any object. Preliminary photometry of the afterglow is following Date UT start t-T0 Filter Exp. OT Err. UL (mid, days) (s) (3 sigma) 2017-11-23 23:31:56 0.41294 R 38*120 n/d n/d 22.2 Photometry is based on nearby USNO-B1.0 stars, R2 magnitude.