TITLE: GCN CIRCULAR NUMBER: 45666 SUBJECT: EP Alert 260921.01: Global MASTER-Net observations report DATE: 26/09/21 01:10:19 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs 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) M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA) MASTER-Tavrida robotic telescope [1] located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the EP Alert 260921.01 (trigger No 1709318601,03h 48m 58.32s , -27d 23m 56.4s, R=0.0508537) errorbox 43 sec after notice time and 396 sec after trigger time at 2026-09-21 00:20:53 UT, with upper limit up to 18.7 mag. The observations began at zenith distance = 74 deg. The sun altitude is -31.5 deg. The galactic latitude b = -50 deg., longitude l = 224 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3508194 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 436 | 2026-09-21 00:20:53 | MASTER-Tavrida | (03h 49m 17.11s , -27d 29m 31.2s) | C | 80 | 18.1 | 436 | 2026-09-21 00:20:53 | MASTER-Tavrida | (03h 49m 11.31s , -27d 28m 04.3s) | C | 80 | 17.6 | 530 | 2026-09-21 00:22:17 | MASTER-Tavrida | (03h 49m 17.77s , -27d 29m 37.4s) | C | 100 | 18.2 | 530 | 2026-09-21 00:22:17 | MASTER-Tavrida | (03h 49m 11.99s , -27d 28m 10.6s) | C | 100 | 18.5 | 644 | 2026-09-21 00:24:01 | MASTER-Tavrida | (03h 49m 18.53s , -27d 29m 43.3s) | C | 120 | 18.1 | 644 | 2026-09-21 00:24:01 | MASTER-Tavrida | (03h 49m 12.77s , -27d 28m 16.8s) | C | 120 | 18.5 | 771 | 2026-09-21 00:26:08 | MASTER-Tavrida | (03h 49m 19.35s , -27d 29m 50.5s) | C | 120 | 18.3 | 771 | 2026-09-21 00:26:08 | MASTER-Tavrida | (03h 49m 13.61s , -27d 28m 23.9s) | C | 120 | 18.5 | 895 | 2026-09-21 00:28:12 | MASTER-Tavrida | (03h 49m 20.09s , -27d 29m 56.4s) | C | 120 | 18.5 | 895 | 2026-09-21 00:28:12 | MASTER-Tavrida | (03h 49m 14.37s , -27d 28m 29.8s) | C | 120 | 18.5 | 1021 | 2026-09-21 00:30:18 | MASTER-Tavrida | (03h 49m 20.84s , -27d 30m 01.9s) | C | 120 | 18.4 | 1022 | 2026-09-21 00:30:18 | MASTER-Tavrida | (03h 49m 15.05s , -27d 28m 35.5s) | C | 120 | 18.5 | 1145 | 2026-09-21 00:32:22 | MASTER-Tavrida | (03h 49m 21.53s , -27d 30m 07.5s) | C | 120 | 18.5 | 1145 | 2026-09-21 00:32:22 | MASTER-Tavrida | (03h 49m 15.73s , -27d 28m 41.0s) | C | 120 | 18.5 | 1272 | 2026-09-21 00:34:29 | MASTER-Tavrida | (03h 49m 22.19s , -27d 30m 13.5s) | C | 120 | 18.5 | 1272 | 2026-09-21 00:34:29 | MASTER-Tavrida | (03h 49m 16.44s , -27d 28m 46.8s) | C | 120 | 18.5 | 1396 | 2026-09-21 00:36:33 | MASTER-Tavrida | (03h 49m 22.81s , -27d 30m 18.9s) | C | 120 | 18.6 | 1396 | 2026-09-21 00:36:33 | MASTER-Tavrida | (03h 49m 17.09s , -27d 28m 52.3s) | C | 120 | 18.6 | 1522 | 2026-09-21 00:38:39 | MASTER-Tavrida | (03h 49m 23.43s , -27d 30m 24.3s) | C | 120 | 18.6 | 1523 | 2026-09-21 00:38:39 | MASTER-Tavrida | (03h 49m 17.72s , -27d 28m 57.3s) | C | 120 | 18.6 | 1646 | 2026-09-21 00:40:43 | MASTER-Tavrida | (03h 49m 24.03s , -27d 30m 29.2s) | C | 120 | 18.6 | 1646 | 2026-09-21 00:40:43 | MASTER-Tavrida | (03h 49m 18.35s , -27d 29m 02.4s) | C | 120 | 18.5 | 1773 | 2026-09-21 00:42:50 | MASTER-Tavrida | (03h 49m 24.60s , -27d 30m 34.2s) | C | 120 | 18.6 | 1773 | 2026-09-21 00:42:50 | MASTER-Tavrida | (03h 49m 18.95s , -27d 29m 07.3s) | C | 120 | 18.6 | 1897 | 2026-09-21 00:44:54 | MASTER-Tavrida | (03h 49m 25.15s , -27d 30m 39.4s) | C | 120 | 18.6 | 1897 | 2026-09-21 00:44:54 | MASTER-Tavrida | (03h 49m 19.50s , -27d 29m 12.3s) | C | 120 | 18.6 | 2023 | 2026-09-21 00:47:00 | MASTER-Tavrida | (03h 49m 25.66s , -27d 30m 45.0s) | C | 120 | 18.6 | 2024 | 2026-09-21 00:47:01 | MASTER-Tavrida | (03h 49m 20.07s , -27d 29m 18.2s) | C | 120 | 18.6 | 2147 | 2026-09-21 00:49:04 | MASTER-Tavrida | (03h 49m 26.21s , -27d 30m 49.7s) | C | 120 | 18.6 | 2148 | 2026-09-21 00:49:05 | MASTER-Tavrida | (03h 49m 20.64s , -27d 29m 22.8s) | C | 120 | 18.6 | 2274 | 2026-09-21 00:51:11 | MASTER-Tavrida | (03h 49m 26.74s , -27d 30m 54.9s) | C | 120 | 18.6 | 2274 | 2026-09-21 00:51:11 | MASTER-Tavrida | (03h 49m 21.13s , -27d 29m 28.1s) | C | 120 | 18.6 | 2398 | 2026-09-21 00:53:15 | MASTER-Tavrida | (03h 49m 27.23s , -27d 30m 59.7s) | C | 120 | 18.6 | 2398 | 2026-09-21 00:53:15 | MASTER-Tavrida | (03h 49m 21.61s , -27d 29m 33.0s) | C | 120 | 18.6 | 2526 | 2026-09-21 00:55:23 | MASTER-Tavrida | (03h 49m 27.71s , -27d 31m 05.1s) | C | 120 | 18.6 | 2526 | 2026-09-21 00:55:23 | MASTER-Tavrida | (03h 49m 22.08s , -27d 29m 38.3s) | C | 120 | 18.5 | 2650 | 2026-09-21 00:57:27 | MASTER-Tavrida | (03h 49m 28.16s , -27d 31m 09.9s) | C | 120 | 18.6 | 2650 | 2026-09-21 00:57:27 | MASTER-Tavrida | (03h 49m 22.50s , -27d 29m 42.9s) | C | 120 | 18.7 | 2774 | 2026-09-21 00:59:31 | MASTER-Tavrida | (03h 49m 28.58s , -27d 31m 14.9s) | C | 120 | 18.6 | 2774 | 2026-09-21 00:59:31 | MASTER-Tavrida | (03h 49m 22.92s , -27d 29m 47.9s) | C | 120 | 18.6 | 2897 | 2026-09-21 01:01:34 | MASTER-Tavrida | (03h 49m 28.99s , -27d 31m 20.3s) | C | 120 | 18.6 | 2898 | 2026-09-21 01:01:35 | MASTER-Tavrida | (03h 49m 23.37s , -27d 29m 53.6s) | C | 120 | 18.6 | 3021 | 2026-09-21 01:03:38 | MASTER-Tavrida | (03h 49m 29.34s , -27d 31m 25.1s) | C | 120 | 18.7 | 3021 | 2026-09-21 01:03:38 | MASTER-Tavrida | (03h 49m 23.77s , -27d 29m 58.5s) | C | 120 | 18.6 | 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