TITLE: GCN CIRCULAR NUMBER: 43142 SUBJECT: GRB 251202A/EP251202a: Koshka optical upper limit DATE: 25/12/16 14:47:43 GMT FROM: Alina Volnova at IKI RAS <alinusss@gmail.com> A. A. Volnova (IKI), A. Novichonok (Petrozavodsk State University, KIAM), A. S. Pozanenko (IKI), N. S. Pankov (HSE, IKI) report on behalf of IKI-GRB-FuN: We observed the field of GRB 251202A/EP251202a (Fermi GBM team, GCN 42933; Zhang et al., GCN 42937; Sbarufatti et al., GCN 42943; Liang et al., GCN 42946; Bala, GCN 42957; Arya et al., GCN 42967; Guo et al., GCN 42970, GCN 42997) with the Zeiss-1000 telescope of the Simeiz (Koshka) observatory (INASAN) taking several 90-second expositions in R-band starting on Dec.05 UT 21:38:48. In the stacked image we do not detect the optical counterpart reported previously (Zhu et al., GCN 42939; O’Neill et al., GCN 42947; Quirola-Vasquez et al., GCN 42948; Kuin and Moss, GCN 42956; Zheng et al., GCN 42964; Ma et al., GCN 42966; Bochenek et al., GCN 42977; Contreras et al., GCN 42999; Giarratana et al., GCN 43128). Preliminary photometry and observational details are the following: Date UT start t-T0 Exp. Filter Obj. Err. UL Site/Telescope (mid,days) (n*s) (3sigma) 2025-12-05 21:38:48 3.86988 68*90 R n/d n/d 19.7 Simeiz/Zeiss-1000 The photometry is based on several 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/43142. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...