TITLE: GCN CIRCULAR NUMBER: 44852 SUBJECT: GRB 260504C: SAO RAS optical observations DATE: 26/06/06 20:42:04 GMT FROM: Alexander Moskvitin at SAO RAS <mosk@sao.ru> A. Moskvitin (SAO RAS), O. Spiridonova (SAO RAS), A. Pozanenko (IKI), A. Volnova (IKI), N. Pankov (IKI) report on behalf of GRB follow-up team We observed the field of long GRB 260604C discovered by Fermi (The Fermi GBM team, GCN 44822; Neights & Meegan, GCN 44831) and SVOM (Gotz et al., GCN 44823) with the Zeiss-1000 1-m telescope of SAO RAS equipped with the CCD photometer. We obtained 12 x 300 sec. images in Rc band on June 05, 22:25:58--23:33:55 UT. The OT (Lipunov, GCN 44827; Konno et al., GCN 44828; GCN 44836; Zhu et al., GCN 44832; Becerra et al., GCN 44834; Hellot et al., GCN 44835; Gompertz et al., GCN 44837; Gompertz et al., GCN 44843; Chen et al.б GCN 44851) is clearly detected in our stacked image with the following brightness: Date UTstart t-T0 Exp. Filter Mag +/- Err. UL (mid,d) (n*s) (3-sigma) 2026.06.05T22:25:58 1.11195 12*300 Rc 21.65 +/- 0.07 23.4 This preliminary photometry is based on nearby SDSS stars (using Lupton 2005 transformation equations) and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/44852. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...