TITLE: GCN CIRCULAR NUMBER: 44395 SUBJECT: EP260416a: ZTSh R band observations DATE: 26/04/22 23:58:50 GMT FROM: Alexander Moskvitin at SAO RAS <mosk@sao.ru> A. Moskvitin (SAO RAS), V. Rumyantsev (CrAO), A. Volnova, N. Pankov, A. Pozanenko (IKI), Tao An, Yuanqi Liu (SHAO), Ankur Ghosh, Soebur Razzaque (U. of Johannesburg, RSA) report on behalf of GRB follow-up collaboration. We observed the field of EP260416a (Hu et al., GCN 44307; GCN 44324) with 2.6-m ZTSh of CrAO equipped with BVRI photometer and FLI PL4240 camera. We obtained a series of images in R band on 2026-04-22, 21:11:50--22:14:42 UT (t_mid - T0 = 6.6762 days). The optical transient discovered by COLIBRÍ (Ducoin et al., GCN 44310; and also observed by Li et al., GCN 44315; Hua et al., GCN 44318; Lee et al., GCN 44319; Martin-Carrillo et al., GCN 44328; Li et al., GCN 44334; He et al., GCN 44336; An et al., GCN 44339; Jelinek et al., GCN 44341; Guziy et al., GCN 44351; Ho et al., GCN 44354) is clearly detected in the stacked image with the following brightness. Date, UT_start, t_mid - T0, filter, exp, mag +/- err UL days s 2026-04-22T21:11:50 6.67620 R 30*120 23.12 +/- 0.17 24.1 This preliminary photometry is based on the nearby USNO-B1 stars and not corrected for the Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/44395. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...