TITLE: GCN CIRCULAR NUMBER: 40899 SUBJECT: GRB 250702F: MASTER optical afterglow observation DATE: 25/07/02 22:49:02 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> V.Lipunov (Lomonosov MSU), D.Buckley (SAAO), A.Kuznetsov, E.Gorbovskoy, G.Antipov, P.Balanutsa, A.Chasovnikov, N.Tiurina, V.Topolev, K.Zhirkov, Ya.Kechin, V.Senik, D.Vlasenko (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (OAFA), A.Sosnovskij (Crao RAS), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory MASTER-SAAO robotic telescope (MASTER Global Robotic Net http://observ.pereplet.ru, Lipunov et al. 2010, Advances in Astronomy, v.2010, 30L) located in South African Astronomical Observatory, pointed (Lipunov et al. GCN 40893) to Fermi (GCN 40892) and Swift GRB 250702F (Klingler et al., GCN 40894, Ttrigger=21:06:43.27UT) in two polarization filters at 2025-07-02 21:24:39 UT ( https://master.sai.msu.ru/site/master2/observ.php?id=2923573 ). There is MASTER OT J141144.70+164454.6 with m_OT~16.2 with preliminary significant polarization. This GRB 250702F counterpartwas discovered by Swift (GCN 40894) and also reported by Ondrejov D50 (Jelinek et al., GCN 20895) and GOTO (Kumar et al. GCN 40896) observatories. Observation and reduction will be continued. View this GCN Circular online at https://gcn.nasa.gov/circulars/40899. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...