TITLE: GCN CIRCULAR NUMBER: 45278 SUBJECT: Fermi GRB 260802B: Global MASTER-Net observations report DATE: 26/08/03 06:45:36 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-SAAO robotic telescope [1] located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 260802B ( Fermi GBM team, GCN 45273) errorbox 37429 sec after notice time and 37470 sec after trigger time at 2026-08-02 19:24:19 UT, with upper limit up to 20.0 mag. The observations began at zenith distance = 23 deg. The sun altitude is -43.4 deg. MASTER-OAFA robotic telescope located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 260802B errorbox 71774 sec after notice time and 71815 sec after trigger time at 2026-08-03 04:56:44 UT, with upper limit up to 20.5 mag. The observations began at zenith distance = 7 deg. The sun altitude is -75.4 deg. The galactic latitude b = -36 deg., longitude l = 29 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3454222 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 37501 | 2026-08-02 19:24:19 | MASTER-SAAO | (19h 17m 14.20s , -42d 47m 11.3s) | C | 60 | 19.5 | 37561 | 2026-08-02 19:24:19 | MASTER-SAAO | (19h 17m 14.20s , -42d 47m 11.3s) | C | 180 | 20.0 | Coadd 38459 | 2026-08-02 19:40:17 | MASTER-SAAO | (19h 17m 07.08s , -42d 45m 56.4s) | C | 60 | 19.4 | 40530 | 2026-08-02 20:14:48 | MASTER-SAAO | (19h 17m 05.30s , -42d 45m 20.8s) | C | 60 | 19.2 | 40590 | 2026-08-02 20:14:48 | MASTER-SAAO | (19h 17m 05.30s , -42d 45m 20.8s) | C | 180 | 19.8 | Coadd 42524 | 2026-08-02 20:48:02 | MASTER-SAAO | (19h 17m 02.10s , -42d 44m 39.2s) | C | 60 | 19.1 | 71846 | 2026-08-03 04:56:44 | MASTER-OAFA | (21h 18m 53.41s , -38d 46m 40.4s) | C | 60 | 19.8 | 71906 | 2026-08-03 04:56:44 | MASTER-OAFA | (21h 18m 53.42s , -38d 46m 40.4s) | C | 180 | 20.5 | Coadd 71922 | 2026-08-03 04:57:59 | MASTER-OAFA | (21h 29m 08.59s , -38d 46m 12.0s) | C | 60 | 19.6 | 71982 | 2026-08-03 04:57:59 | MASTER-OAFA | (21h 29m 08.59s , -38d 46m 12.0s) | C | 180 | 19.9 | Coadd 71998 | 2026-08-03 04:59:16 | MASTER-OAFA | (21h 29m 15.65s , -38d 47m 09.5s) | C | 60 | 18.1 | 72074 | 2026-08-03 05:00:31 | MASTER-OAFA | (21h 29m 09.99s , -38d 48m 07.2s) | C | 60 | 19.6 | 72151 | 2026-08-03 05:01:49 | MASTER-OAFA | (21h 29m 15.95s , -38d 47m 37.3s) | C | 60 | 19.6 | 72211 | 2026-08-03 05:01:49 | MASTER-OAFA | (21h 29m 15.94s , -38d 47m 37.4s) | C | 180 | 20.3 | Coadd 72227 | 2026-08-03 05:03:05 | MASTER-OAFA | (21h 29m 12.55s , -38d 46m 02.4s) | C | 60 | 19.8 | 72304 | 2026-08-03 05:04:22 | MASTER-OAFA | (21h 18m 58.01s , -38d 47m 19.2s) | C | 60 | 19.8 | 72380 | 2026-08-03 05:05:38 | MASTER-OAFA | (21h 29m 16.11s , -38d 46m 21.1s) | C | 60 | 19.8 | 72458 | 2026-08-03 05:06:56 | MASTER-OAFA | (21h 18m 55.88s , -38d 46m 20.1s) | C | 60 | 19.8 | 72778 | 2026-08-03 05:12:16 | MASTER-OAFA | (21h 14m 35.17s , -40d 40m 47.0s) | C | 60 | 19.5 | 72838 | 2026-08-03 05:12:16 | MASTER-OAFA | (21h 14m 35.17s , -40d 40m 47.0s) | C | 180 | 20.2 | Coadd 72854 | 2026-08-03 05:13:32 | MASTER-OAFA | (21h 25m 10.51s , -40d 39m 41.0s) | C | 60 | 19.6 | 72914 | 2026-08-03 05:13:32 | MASTER-OAFA | (21h 25m 10.51s , -40d 39m 41.0s) | C | 180 | 20.4 | Coadd 72929 | 2026-08-03 05:14:47 | MASTER-OAFA | (21h 25m 04.54s , -40d 40m 32.6s) | C | 60 | 19.8 | 73007 | 2026-08-03 05:16:04 | MASTER-OAFA | (21h 25m 04.71s , -40d 39m 30.2s) | C | 60 | 19.7 | 73084 | 2026-08-03 05:17:22 | MASTER-OAFA | (21h 14m 39.13s , -40d 39m 54.5s) | C | 60 | 19.3 | 73159 | 2026-08-03 05:18:37 | MASTER-OAFA | (21h 14m 32.10s , -40d 40m 51.7s) | C | 60 | 19.5 | 73237 | 2026-08-03 05:19:55 | MASTER-OAFA | (21h 14m 39.11s , -40d 40m 21.5s) | C | 60 | 19.6 | 73315 | 2026-08-03 05:21:13 | MASTER-OAFA | (21h 25m 08.28s , -40d 39m 48.9s) | C | 60 | 19.5 | 73392 | 2026-08-03 05:22:30 | MASTER-OAFA | (21h 14m 36.58s , -40d 40m 20.7s) | C | 60 | 19.5 | 73866 | 2026-08-03 05:30:24 | MASTER-OAFA | (21h 34m 38.32s , -40d 40m 07.8s) | C | 60 | 19.7 | 73926 | 2026-08-03 05:30:24 | MASTER-OAFA | (21h 34m 38.32s , -40d 40m 07.8s) | C | 180 | 20.2 | Coadd 73941 | 2026-08-03 05:31:39 | MASTER-OAFA | (21h 45m 10.46s , -40d 41m 41.8s) | C | 60 | 19.6 | 74001 | 2026-08-03 05:31:39 | MASTER-OAFA | (21h 45m 10.46s , -40d 41m 41.7s) | C | 180 | 20.0 | Coadd 74020 | 2026-08-03 05:32:57 | MASTER-OAFA | (21h 45m 14.27s , -40d 40m 20.0s) | C | 60 | 19.3 | 74096 | 2026-08-03 05:34:14 | MASTER-OAFA | (21h 45m 07.90s , -40d 41m 03.5s) | C | 60 | 19.2 | 74171 | 2026-08-03 05:35:29 | MASTER-OAFA | (21h 45m 07.02s , -40d 40m 01.0s) | C | 60 | 19.4 | 74231 | 2026-08-03 05:35:29 | MASTER-OAFA | (21h 45m 07.02s , -40d 40m 01.0s) | C | 180 | 20.0 | Coadd 74248 | 2026-08-03 05:36:46 | MASTER-OAFA | (21h 45m 13.98s , -40d 40m 59.3s) | C | 60 | 19.2 | 74326 | 2026-08-03 05:38:04 | MASTER-OAFA | (21h 34m 36.09s , -40d 41m 24.7s) | C | 60 | 19.5 | 74403 | 2026-08-03 05:39:21 | MASTER-OAFA | (21h 45m 15.08s , -40d 41m 26.3s) | C | 60 | 19.6 | 74479 | 2026-08-03 05:40:37 | MASTER-OAFA | (21h 34m 39.72s , -40d 39m 28.3s) | C | 60 | 19.5 | 74555 | 2026-08-03 05:41:53 | MASTER-OAFA | (21h 29m 17.38s , -38d 46m 43.4s) | C | 60 | 19.0 | 74629 | 2026-08-03 05:43:07 | MASTER-OAFA | (21h 29m 21.21s , -38d 45m 08.4s) | C | 60 | 19.2 | 75908 | 2026-08-03 06:04:25 | MASTER-OAFA | (22h 56m 32.11s , -11d 47m 43.6s) | C | 60 | 19.0 | 75968 | 2026-08-03 06:04:25 | MASTER-OAFA | (22h 56m 32.11s , -11d 47m 43.6s) | C | 180 | 19.6 | Coadd 75981 | 2026-08-03 06:05:39 | MASTER-OAFA | (22h 56m 37.44s , -11d 48m 44.6s) | C | 60 | 18.9 | 76059 | 2026-08-03 06:06:57 | MASTER-OAFA | (22h 56m 30.45s , -11d 49m 45.7s) | C | 60 | 18.9 | 76164 | 2026-08-03 06:08:12 | MASTER-OAFA | (22h 56m 37.17s , -11d 49m 41.0s) | C | 120 | 19.3 | 76284 | 2026-08-03 06:08:12 | MASTER-OAFA | (22h 56m 37.17s , -11d 49m 41.0s) | C | 360 | 19.8 | Coadd 76301 | 2026-08-03 06:10:29 | MASTER-OAFA | (22h 56m 34.06s , -11d 48m 12.0s) | C | 120 | 18.9 | 76439 | 2026-08-03 06:12:47 | MASTER-OAFA | (22h 56m 33.86s , -11d 49m 44.5s) | C | 120 | 18.8 | 76574 | 2026-08-03 06:15:02 | MASTER-OAFA | (22h 56m 36.54s , -11d 48m 15.0s) | C | 120 | 18.9 | 76694 | 2026-08-03 06:15:02 | MASTER-OAFA | (22h 56m 36.54s , -11d 48m 15.1s) | C | 360 | 19.6 | Coadd 76713 | 2026-08-03 06:17:21 | MASTER-OAFA | (22h 56m 29.81s , -11d 48m 59.0s) | C | 120 | 19.0 | 76850 | 2026-08-03 06:19:38 | MASTER-OAFA | (22h 56m 30.26s , -11d 48m 02.5s) | C | 120 | 18.9 | 76964 | 2026-08-03 06:22:02 | MASTER-OAFA | (20h 52m 21.01s , -18d 34m 06.6s) | C | 60 | 17.8 | 77024 | 2026-08-03 06:22:02 | MASTER-OAFA | (20h 52m 21.01s , -18d 34m 06.6s) | C | 180 | 17.2 | Coadd 77038 | 2026-08-03 06:23:16 | MASTER-OAFA | (20h 52m 14.06s , -18d 35m 09.0s) | C | 60 | 16.3 | 77116 | 2026-08-03 06:24:34 | MASTER-OAFA | (20h 52m 20.49s , -18d 35m 03.7s) | C | 60 | 13.6 | 77223 | 2026-08-03 06:25:51 | MASTER-OAFA | (20h 52m 17.12s , -18d 33m 47.2s) | C | 120 | 18.4 | 77343 | 2026-08-03 06:25:51 | MASTER-OAFA | (20h 52m 17.13s , -18d 33m 47.2s) | C | 360 | 19.7 | Coadd 77361 | 2026-08-03 06:28:08 | MASTER-OAFA | (20h 52m 17.05s , -18d 34m 58.9s) | C | 120 | 19.2 | 77497 | 2026-08-03 06:30:25 | MASTER-OAFA | (20h 52m 20.90s , -18d 33m 30.0s) | C | 120 | 19.6 | 77682 | 2026-08-03 06:33:29 | MASTER-OAFA | (20h 52m 35.71s , -18d 32m 24.3s) | C | 120 | 19.7 | 77817 | 2026-08-03 06:35:44 | MASTER-OAFA | (20h 52m 36.79s , -18d 31m 22.2s) | C | 120 | 19.3 | 77954 | 2026-08-03 06:38:02 | MASTER-OAFA | (20h 52m 42.22s , -18d 32m 20.9s) | C | 120 | 18.9 | 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/45278. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...