TITLE: GCN CIRCULAR NUMBER: 42897 SUBJECT: GRB 251129A / EP251129a: SAO RAS optical observations DATE: 25/11/29 17:59:49 GMT FROM: Alexander Moskvitin at SAO RAS <mosk@sao.ru> A. S. Moskvitin and O. I. Spiridonova (SAO RAS) report on behalf of GRB follow-up team. We observed the field of the SVOM GRB 251129A (Tan et al., GCN 42877) also detected by Einstein Probe as EP251129a (Wu et al., GCN 42884) and Swift (Evans, GCN 42888; Page et al., GCN 42891) with the Zeiss-1000 1m telescope of the SAO RAS on November 29, 15:27:01--16:00:22 UT (t_mid - T0 = 0.54973 days). We obtained 6 * 300 sec images in Rc band. The optical afterglow (Angulo et al., GCN 42880; Wu et al., GCN 42882; Watson, GCN 42883; Masi, GCN 42885; Li et al., GCN 42887; Lipunov et al., GCN 42892) is clearly detected in the stacked frame with the following brightness. Date UT start t-T0 Exp. Filter OT Err. UL (mid,days) (n*s) (3sigma) 2025-11-29 15:27:01 0.54973 6*300 Rc 21.00 0.07 22.8 This preliminary 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/42897. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...