TITLE: GCN CIRCULAR NUMBER: 43451 SUBJECT: GRB 260117A: ZTSh optical upper limit DATE: 26/01/19 11:53:13 GMT FROM: Alina Volnova at IKI RAS <alinusss@gmail.com> A. A. Volnova (IKI), V. Rumyantsev (CrAO), N. Pankov (HSE, IKI), A. S. Pozanenko (IKI) report on behalf of IKI-GRB-FuN: We observed the field of the SVOM GRB 260117A (Palmerio et al., GCN Circ. 43437) with the ZTSH telescope of CrAO starting on 2026-01-18 at 20:50:34 UT and taking several 120s exposures in R-band. At the position of the source detected by Swift/XRT (Salvaggio et al., GCN 43439; Evans et al., GCN 43438) we do not detect the optical source reported previously by SVOM/VT (Li et al., GCN Circ. 43441) and SVOM/COLIBRÍ (FM-GFT; Fortin et al., GCN 43445). Preliminary photometry is the following: Date UT start t-T0 Exp. Filter Obj. Err. UL Site/Telescope (mid,days) (n*s) (3sigma) 2026-01-18 20:50:34 1.07354 37*120 R n/d n/d 23.2 CrAO/ZTSh The photometry is based on nearby stars from the USNO-B1 catalogue (R2 magnitudes) and is not corrected for the Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/43451. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...