TITLE: GCN CIRCULAR NUMBER: 38732 SUBJECT: GRB 241229B: CrAO ZTSh possible optical counterpart of SVOM/VT confirmation DATE: 24/12/30 20:16:39 GMT FROM: Alexei Pozanenko at IKI, Moscow <grb.alex@gmail.com> A. Volnova (IKI), A. Pozanenko (IKI), V. Rumyantsev (CrAO), N. Pankov (HSE, IKI) report on behalf of GRB-IKI-FuN collaboration: We observed the GRB 241229B (Fermi GBM Team, GCN 38698; D'Ai et al., GCN 38699) with 2.6-meter ZTSh telescope of CrAO. The observations started on 2024-12-29 (UT) 20:22:02, i.e. ~15.4 hours after GBM trigger. We clearly detected SVOM/VT optical candidate (SVOM/VT team, GCN 38729). The preliminary photometry of the the optical candidate is the following: Date UT start T0+ Exp. Filter OT Err. UL(3sigma) (mid, days) (s) 2024-12-29 20:22:02 0.64631 88x120 R 21.91 0.05 24.2 The magnitudes are calibrated using nearby Pan-Starrs PS1 (transformed into R by Lupton's transformations) RA Dec R_Lupton 18:16:50.10 +74:41:42.2 18.928 +- 0.020 18:16:33.99 +74:41:43.6 18.778 +- 0.026 18:16:26.64 +74:41:33.2 17.917 +- 0.014 View this GCN Circular online at https://gcn.nasa.gov/circulars/38732. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...