TITLE: GCN CIRCULAR NUMBER: 30321 SUBJECT: Fermi GRB 210625A: Global MASTER-Net observations report DATE: 21/06/25 23:05:14 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University) MASTER-IAC robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Spain (IAC Teide Observatory) started inspect of the Fermi GRB 210625A ( Fermi GBM team, GCN 30319) errorbox 1261 sec after notice time and 1355 sec after trigger time at 2021-06-25 21:45:56 UT, with upper limit up to 16.7 mag. The observations began at zenith distance = 71 deg. The sun altitude is -19.6 deg. MASTER-OAFA robotic telescope located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 210625A errorbox 4020 sec after notice time and 4114 sec after trigger time at 2021-06-25 22:31:55 UT, with upper limit up to 16.3 mag. Observations started at twilight. The observations began at zenith distance = 55 deg. The sun altitude is -10.7 deg. The galactic latitude b = 5 deg., longitude l = 341 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1644880 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 1386 | 2021-06-25 21:45:56 | MASTER-IAC | (16h 24m 25.20s , -40d 31m 27.3s) | C | 60 | 16.7 | 1386 | 2021-06-25 21:45:56 | MASTER-IAC | (16h 13m 53.49s , -40d 25m 50.0s) | C | 60 | 16.5 | 1467 | 2021-06-25 21:47:18 | MASTER-IAC | (16h 33m 17.35s , -42d 26m 47.4s) | C | 60 | 16.7 | 1467 | 2021-06-25 21:47:18 | MASTER-IAC | (16h 22m 26.85s , -42d 21m 11.0s) | C | 60 | 16.5 | 1547 | 2021-06-25 21:48:38 | MASTER-IAC | (16h 44m 26.10s , -40d 34m 09.7s) | C | 60 | 16.4 | 1547 | 2021-06-25 21:48:38 | MASTER-IAC | (16h 33m 54.14s , -40d 28m 33.9s) | C | 60 | 16.5 | 4144 | 2021-06-25 22:31:55 | MASTER-OAFA | (16h 43m 49.19s , -39d 20m 37.5s) | C | 60 | 13.6 | 4303 | 2021-06-25 22:34:34 | MASTER-OAFA | (16h 20m 16.83s , -46d 55m 09.0s) | C | 60 | 12.2 | 4382 | 2021-06-25 22:35:53 | MASTER-OAFA | (16h 31m 50.58s , -46d 57m 05.9s) | C | 60 | 13.5 | 4462 | 2021-06-25 22:37:12 | MASTER-OAFA | (15h 58m 15.24s , -46d 55m 21.8s) | C | 60 | 16.3 | 4541 | 2021-06-25 22:38:32 | MASTER-OAFA | (16h 09m 49.77s , -46d 54m 40.3s) | C | 60 | 15.6 | 4620 | 2021-06-25 22:39:51 | MASTER-OAFA | (15h 47m 49.38s , -45d 02m 04.1s) | C | 60 | 16.0 | 4700 | 2021-06-25 22:41:11 | MASTER-OAFA | (15h 59m 06.20s , -45d 02m 10.7s) | C | 60 | 16.0 | 4779 | 2021-06-25 22:42:30 | MASTER-OAFA | (16h 42m 15.43s , -46d 57m 07.4s) | C | 60 | 13.7 | 4860 | 2021-06-25 22:43:50 | MASTER-OAFA | (16h 53m 52.94s , -46d 56m 21.1s) | C | 60 | 15.4 | 4939 | 2021-06-25 22:45:10 | MASTER-OAFA | (16h 51m 33.32s , -45d 01m 53.0s) | C | 60 | 15.3 | 5019 | 2021-06-25 22:46:29 | MASTER-OAFA | (17h 02m 50.38s , -45d 03m 13.9s) | C | 60 | 14.1 | 5098 | 2021-06-25 22:47:49 | MASTER-OAFA | (16h 43m 44.44s , -39d 21m 39.0s) | C | 60 | 13.9 | 5179 | 2021-06-25 22:49:09 | MASTER-OAFA | (16h 54m 03.63s , -39d 21m 28.4s) | C | 60 | 12.2 | 5258 | 2021-06-25 22:50:29 | MASTER-OAFA | (16h 20m 17.35s , -46d 55m 04.3s) | C | 60 | 12.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.