TITLE: GCN CIRCULAR NUMBER: 45055 SUBJECT: Fermi GRB 260628A: Global MASTER-Net observations report DATE: 26/06/29 03:33:42 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), 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-OAGH robotic telescope [1] located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the Fermi GRB 260628A ( Fermi GBM team, GCN 45053) errorbox 19512 sec after notice time and 19564 sec after trigger time at 2026-06-29 03:17:28 UT, with upper limit up to 15.9 mag. Observations started at twilight. The observations began at zenith distance = 81 deg. The sun altitude is -9.9 deg. The galactic latitude b = -26 deg., longitude l = 39 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3405318 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 19595 | 2026-06-29 03:17:28 | MASTER-OAGH | (19h 41m 35.39s , +00d 26m 15.1s) | C | 60 | 14.6 | 19821 | 2026-06-29 03:21:14 | MASTER-OAGH | (19h 41m 18.87s , -01d 27m 54.5s) | C | 60 | 15.0 | 19821 | 2026-06-29 03:21:14 | MASTER-OAGH | (19h 35m 27.78s , -00d 49m 53.7s) | C | 60 | 14.5 | 19901 | 2026-06-29 03:22:35 | MASTER-OAGH | (19h 43m 03.30s , +02d 19m 13.8s) | C | 60 | 15.4 | 20056 | 2026-06-29 03:25:10 | MASTER-OAGH | (19h 47m 54.90s , +02d 57m 54.9s) | C | 60 | 14.9 | 20056 | 2026-06-29 03:25:10 | MASTER-OAGH | (19h 53m 46.15s , +02d 19m 54.0s) | C | 60 | 15.4 | 20137 | 2026-06-29 03:26:30 | MASTER-OAGH | (19h 45m 51.59s , +04d 13m 03.3s) | C | 60 | 15.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/45055. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...