TITLE: GCN CIRCULAR NUMBER: 44929 SUBJECT: GRB 260610B / AT2026owq: further SAO RAS optical observations DATE: 26/06/13 06:35:11 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 GRB 260610B discovered by Fermi (The Fermi GBM team, GCN 44891; GCN 44901) with the Zeiss-1000 1-m telescope of SAO RAS + CCD photometer in BVRcIc filters on June 12. The OT (O'Neill et al., GCN 44903; Watson et al., GCN 44905; Zhu et al., GCN 44909; Gillanders et al., GCN 44910; Akl et al., GCN 44911; O'Neill et al., GCN 44914; Moskvitin et al., GCN 44918; Jackson-Horne et al., GCN 44919; Izzo, GCN 44920; Li et al., GCN 44921; Bochenek and Perley, GCN 44927) is clearly detected in our frames with the following brightness: Date, UTstart, t-T0, Exp., Filter, Mag, Err., UL (mid,d) (n*s) (3-sigma) 2026-06-12 19:21:03 2.41821 5*300 Rc 20.61 0.03 23.5 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/44929. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...