TITLE: GCN CIRCULAR NUMBER: 45791 SUBJECT: Fermi GRB 260930B: Global MASTER-Net observations report DATE: 26/10/01 08:45:41 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA) 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 (Lomonosov MSU) D.Buckley (SAAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) A.Sosnovskij (Lomonosov MSU) A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory) L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) R.Rebolo (The Instituto de Astrofisica de Canarias) O.Gress, N.Budnev(ISU) MASTER-Tavrida robotic telescope [1] located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB 260930B ( Fermi GBM team, GCN 45789) errorbox 17491 sec after notice time and 17522 sec after trigger time at 2026-09-30 23:49:00 UT, with upper limit up to 14.4 mag. The observations began at zenith distance = 43 deg. The sun altitude is -38.6 deg. MASTER-OAFA robotic telescope located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 260930B errorbox 48817 sec after notice time and 48847 sec after trigger time at 2026-10-01 08:31:05 UT, with upper limit up to 18.0 mag. The observations began at zenith distance = 79 deg. The sun altitude is -22.2 deg. The galactic latitude b = 20 deg., longitude l = 173 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3515988 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 17552 | 2026-09-30 23:49:00 | MASTER-Tavrida | (06h 51m 49.85s , +44d 03m 29.3s) | C | 60 | 14.4 | 48878 | 2026-10-01 08:31:05 | MASTER-OAFA | (07h 13m 36.47s , +37d 24m 41.7s) | C | 60 | 17.3 | 48938 | 2026-10-01 08:31:05 | MASTER-OAFA | (07h 13m 36.45s , +37d 24m 41.6s) | C | 180 | 18.0 | Coadd 49101 | 2026-10-01 08:34:49 | MASTER-OAFA | (07h 13m 41.79s , +37d 23m 09.4s) | C | 60 | 17.4 | 49176 | 2026-10-01 08:36:04 | MASTER-OAFA | (07h 13m 37.87s , +37d 24m 24.9s) | C | 60 | 17.6 | 49329 | 2026-10-01 08:38:36 | MASTER-OAFA | (07h 13m 41.02s , +37d 24m 23.0s) | C | 60 | 17.5 | 49407 | 2026-10-01 08:39:54 | MASTER-OAFA | (06h 57m 17.58s , +41d 11m 09.5s) | C | 60 | 17.3 | 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/45791. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...