TITLE: GCN CIRCULAR NUMBER: 44784 SUBJECT: Fermi GRB 260602B: Global MASTER-Net observations report DATE: 26/06/03 03:35:27 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-OAFA robotic telescope [1] located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 260602B ( Fermi GBM team, GCN 44779) errorbox 9521 sec after notice time and 9563 sec after trigger time at 2026-06-03 01:20:54 UT, with upper limit up to 20.0 mag. The observations began at zenith distance = 23 deg. The sun altitude is -46.3 deg. MASTER-OAGH robotic telescope located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the Fermi GRB 260602B errorbox 16498 sec after notice time and 16540 sec after trigger time at 2026-06-03 03:17:11 UT, with upper limit up to 17.3 mag. Observations started at twilight. The observations began at zenith distance = 45 deg. The sun altitude is -11.4 deg. The galactic latitude b = 46 deg., longitude l = 298 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3356506 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 9594 | 2026-06-03 01:20:54 | MASTER-OAFA | (12h 27m 05.82s , -13d 47m 16.2s) | C | 60 | 19.1 | 9654 | 2026-06-03 01:20:54 | MASTER-OAFA | (12h 27m 05.83s , -13d 47m 16.2s) | C | 180 | 19.4 | Coadd 9670 | 2026-06-03 01:22:10 | MASTER-OAFA | (12h 35m 13.14s , -13d 48m 26.4s) | C | 60 | 18.9 | 9730 | 2026-06-03 01:22:10 | MASTER-OAFA | (12h 35m 13.13s , -13d 48m 26.4s) | C | 180 | 19.2 | Coadd 9750 | 2026-06-03 01:23:31 | MASTER-OAFA | (12h 27m 05.16s , -13d 47m 57.0s) | C | 60 | 19.0 | 9828 | 2026-06-03 01:24:48 | MASTER-OAFA | (12h 35m 17.15s , -13d 46m 53.5s) | C | 60 | 18.8 | 9903 | 2026-06-03 01:26:04 | MASTER-OAFA | (12h 27m 02.72s , -13d 48m 07.0s) | C | 60 | 18.7 | 9985 | 2026-06-03 01:27:26 | MASTER-OAFA | (12h 26m 59.87s , -13d 47m 08.8s) | C | 60 | 18.5 | 10045 | 2026-06-03 01:27:26 | MASTER-OAFA | (12h 26m 59.86s , -13d 47m 08.8s) | C | 180 | 19.1 | Coadd 10078 | 2026-06-03 01:28:59 | MASTER-OAFA | (12h 35m 14.02s , -13d 46m 18.6s) | C | 60 | 18.5 | 10154 | 2026-06-03 01:30:15 | MASTER-OAFA | (12h 27m 05.70s , -13d 47m 05.8s) | C | 60 | 18.5 | 10235 | 2026-06-03 01:31:36 | MASTER-OAFA | (12h 35m 14.80s , -13d 48m 15.9s) | C | 60 | 18.6 | 10295 | 2026-06-03 01:31:36 | MASTER-OAFA | (12h 35m 14.79s , -13d 48m 15.9s) | C | 180 | 19.6 | Coadd 10312 | 2026-06-03 01:32:53 | MASTER-OAFA | (12h 27m 05.42s , -13d 48m 01.8s) | C | 60 | 18.8 | 10390 | 2026-06-03 01:34:10 | MASTER-OAFA | (12h 25m 20.90s , -17d 35m 31.1s) | C | 60 | 18.9 | 10450 | 2026-06-03 01:34:10 | MASTER-OAFA | (12h 25m 20.90s , -17d 35m 31.1s) | C | 180 | 19.6 | Coadd 10467 | 2026-06-03 01:35:27 | MASTER-OAFA | (12h 33m 47.10s , -17d 34m 19.6s) | C | 60 | 18.7 | 10527 | 2026-06-03 01:35:27 | MASTER-OAFA | (12h 33m 47.11s , -17d 34m 19.6s) | C | 180 | 19.2 | Coadd 10547 | 2026-06-03 01:36:48 | MASTER-OAFA | (12h 33m 40.74s , -17d 34m 01.3s) | C | 60 | 18.1 | 10613 | 2026-06-03 01:37:54 | MASTER-OAFA | (12h 33m 40.67s , -17d 34m 00.6s) | C | 60 | 18.8 | 10684 | 2026-06-03 01:39:05 | MASTER-OAFA | (12h 25m 23.88s , -17d 34m 49.3s) | C | 60 | 19.0 | 10772 | 2026-06-03 01:40:33 | MASTER-OAFA | (12h 25m 23.93s , -17d 35m 34.0s) | C | 60 | 19.0 | 10848 | 2026-06-03 01:41:49 | MASTER-OAFA | (12h 33m 44.40s , -17d 34m 11.7s) | C | 60 | 18.7 | 10908 | 2026-06-03 01:41:49 | MASTER-OAFA | (12h 33m 44.40s , -17d 34m 11.7s) | C | 180 | 19.5 | Coadd 10925 | 2026-06-03 01:43:05 | MASTER-OAFA | (12h 25m 21.11s , -17d 35m 36.9s) | C | 60 | 18.5 | 11002 | 2026-06-03 01:44:23 | MASTER-OAFA | (12h 33m 48.05s , -17d 34m 23.8s) | C | 60 | 18.8 | 11098 | 2026-06-03 01:45:59 | MASTER-OAFA | (12h 25m 17.61s , -17d 34m 43.3s) | C | 60 | 18.8 | 11175 | 2026-06-03 01:47:16 | MASTER-OAFA | (12h 33m 50.32s , -19d 28m 49.0s) | C | 60 | 18.6 | 11235 | 2026-06-03 01:47:16 | MASTER-OAFA | (12h 33m 50.32s , -19d 28m 49.0s) | C | 180 | 19.1 | Coadd 11279 | 2026-06-03 01:49:00 | MASTER-OAFA | (12h 33m 50.36s , -19d 29m 26.5s) | C | 60 | 18.6 | 11356 | 2026-06-03 01:50:17 | MASTER-OAFA | (12h 42m 16.13s , -19d 28m 13.0s) | C | 60 | 19.0 | 11416 | 2026-06-03 01:50:17 | MASTER-OAFA | (12h 42m 16.13s , -19d 28m 13.0s) | C | 180 | 19.8 | Coadd 11432 | 2026-06-03 01:51:33 | MASTER-OAFA | (12h 33m 47.20s , -19d 29m 21.2s) | C | 60 | 18.2 | 11498 | 2026-06-03 01:52:39 | MASTER-OAFA | (12h 57m 10.66s , -17d 35m 20.6s) | C | 60 | 18.8 | 11558 | 2026-06-03 01:52:39 | MASTER-OAFA | (12h 57m 10.66s , -17d 35m 20.6s) | C | 180 | 19.7 | Coadd 12298 | 2026-06-03 02:05:59 | MASTER-OAFA | (13h 05m 37.50s , -17d 36m 14.8s) | C | 60 | 19.4 | 12358 | 2026-06-03 02:05:59 | MASTER-OAFA | (13h 05m 37.50s , -17d 36m 14.8s) | C | 180 | 19.8 | Coadd 12375 | 2026-06-03 02:07:16 | MASTER-OAFA | (12h 57m 18.25s , -17d 34m 48.1s) | C | 60 | 19.1 | 12453 | 2026-06-03 02:08:34 | MASTER-OAFA | (13h 05m 34.06s , -17d 35m 30.3s) | C | 60 | 19.1 | 12529 | 2026-06-03 02:09:50 | MASTER-OAFA | (12h 57m 11.85s , -17d 34m 15.1s) | C | 60 | 19.5 | 12607 | 2026-06-03 02:11:08 | MASTER-OAFA | (12h 35m 21.57s , -13d 46m 50.3s) | C | 60 | 19.5 | 12691 | 2026-06-03 02:12:32 | MASTER-OAFA | (12h 35m 17.62s , -13d 47m 19.1s) | C | 60 | 19.5 | 12783 | 2026-06-03 02:14:03 | MASTER-OAFA | (12h 33m 41.62s , -17d 35m 40.6s) | C | 60 | 19.5 | 12860 | 2026-06-03 02:15:20 | MASTER-OAFA | (12h 33m 48.15s , -17d 35m 16.2s) | C | 60 | 19.6 | 12920 | 2026-06-03 02:15:20 | MASTER-OAFA | (12h 33m 48.15s , -17d 35m 16.2s) | C | 180 | 20.0 | Coadd 12943 | 2026-06-03 02:16:44 | MASTER-OAFA | (12h 33m 44.94s , -17d 33m 47.4s) | C | 60 | 19.6 | 13038 | 2026-06-03 02:18:18 | MASTER-OAFA | (12h 33m 48.58s , -17d 33m 59.3s) | C | 60 | 19.3 | 13114 | 2026-06-03 02:19:34 | MASTER-OAFA | (12h 33m 41.07s , -17d 34m 36.6s) | C | 60 | 19.3 | 13193 | 2026-06-03 02:20:54 | MASTER-OAFA | (12h 33m 41.82s , -17d 33m 35.9s) | C | 60 | 19.4 | 13272 | 2026-06-03 02:22:13 | MASTER-OAFA | (12h 42m 13.61s , -19d 29m 40.3s) | C | 60 | 19.1 | 13351 | 2026-06-03 02:23:32 | MASTER-OAFA | (12h 42m 20.13s , -19d 29m 30.9s) | C | 60 | 19.2 | 13427 | 2026-06-03 02:24:48 | MASTER-OAFA | (12h 42m 16.91s , -19d 28m 04.8s) | C | 60 | 19.2 | 13503 | 2026-06-03 02:26:04 | MASTER-OAFA | (12h 33m 47.96s , -19d 29m 08.3s) | C | 60 | 19.5 | 13580 | 2026-06-03 02:27:20 | MASTER-OAFA | (12h 33m 50.86s , -19d 27m 42.5s) | C | 60 | 19.4 | 13680 | 2026-06-03 02:29:00 | MASTER-OAFA | (12h 35m 28.54s , -21d 21m 26.8s) | C | 60 | 19.6 | 13755 | 2026-06-03 02:30:16 | MASTER-OAFA | (12h 35m 36.14s , -21d 22m 26.3s) | C | 60 | 19.4 | 13839 | 2026-06-03 02:31:40 | MASTER-OAFA | (12h 49m 32.63s , -15d 39m 55.0s) | C | 60 | 19.4 | 13930 | 2026-06-03 02:33:11 | MASTER-OAFA | (12h 57m 44.22s , -15d 40m 57.7s) | C | 60 | 19.4 | 13990 | 2026-06-03 02:33:11 | MASTER-OAFA | (12h 57m 44.22s , -15d 40m 57.8s) | C | 180 | 19.8 | Coadd 14009 | 2026-06-03 02:34:30 | MASTER-OAFA | (12h 57m 51.10s , -15d 40m 56.7s) | C | 60 | 19.3 | 14092 | 2026-06-03 02:35:53 | MASTER-OAFA | (12h 57m 48.25s , -15d 40m 23.1s) | C | 60 | 19.5 | 14179 | 2026-06-03 02:37:19 | MASTER-OAFA | (12h 57m 48.26s , -15d 41m 48.9s) | C | 60 | 19.3 | 14261 | 2026-06-03 02:38:42 | MASTER-OAFA | (13h 05m 40.78s , -17d 34m 19.7s) | C | 60 | 19.5 | 14333 | 2026-06-03 02:39:54 | MASTER-OAFA | (13h 05m 35.77s , -17d 35m 00.3s) | C | 60 | 19.4 | 14415 | 2026-06-03 02:41:16 | MASTER-OAFA | (13h 05m 42.30s , -17d 34m 59.5s) | C | 60 | 18.8 | 14494 | 2026-06-03 02:42:35 | MASTER-OAFA | (12h 57m 12.14s , -17d 35m 48.3s) | C | 60 | 19.4 | 14554 | 2026-06-03 02:42:35 | MASTER-OAFA | (12h 57m 12.14s , -17d 35m 48.3s) | C | 180 | 19.9 | Coadd 14573 | 2026-06-03 02:43:54 | MASTER-OAFA | (12h 57m 18.62s , -17d 35m 22.0s) | C | 60 | 19.4 | 14648 | 2026-06-03 02:45:08 | MASTER-OAFA | (12h 57m 15.39s , -17d 34m 02.6s) | C | 60 | 19.3 | 14726 | 2026-06-03 02:46:27 | MASTER-OAFA | (12h 57m 15.42s , -17d 35m 38.7s) | C | 60 | 19.3 | 14819 | 2026-06-03 02:48:00 | MASTER-OAFA | (13h 05m 20.11s , -15d 40m 05.6s) | C | 60 | 19.3 | 16571 | 2026-06-03 03:17:11 | MASTER-OAGH | (12h 28m 33.45s , -14d 00m 32.3s) | C | 60 | 17.3 | 16671 | 2026-06-03 03:18:52 | MASTER-OAGH | (12h 33m 22.10s , -17d 46m 24.2s) | 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/44784. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...