TITLE: GCN CIRCULAR NUMBER: 30608 SUBJECT: Fermi GRB 210807B: Global MASTER-Net observations report DATE: 21/08/07 21:30:37 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 210807B ( Fermi GBM team, GCN 30601) errorbox 28908 sec after notice time and 28937 sec after trigger time at 2021-08-07 20:38:59 UT, with upper limit up to 18.0 mag. Observations started at twilight. The observations began at zenith distance = 60 deg. The sun altitude is -11.2 deg. The galactic latitude b = 5 deg., longitude l = 353 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1683395 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 28967 | 2021-08-07 20:38:59 | MASTER-IAC | (17h 12m 56.82s , -31d 05m 11.5s) | C | 60 | 16.1 | 28967 | 2021-08-07 20:38:59 | MASTER-IAC | (17h 03m 35.72s , -30d 59m 44.0s) | C | 60 | 16.0 | 29047 | 2021-08-07 20:40:20 | MASTER-IAC | (17h 16m 35.97s , -33d 00m 24.9s) | C | 60 | 16.6 | 29047 | 2021-08-07 20:40:20 | MASTER-IAC | (17h 07m 03.20s , -32d 54m 57.0s) | C | 60 | 16.1 | 29127 | 2021-08-07 20:41:40 | MASTER-IAC | (16h 48m 51.47s , -32d 55m 34.2s) | C | 60 | 16.6 | 29127 | 2021-08-07 20:41:40 | MASTER-IAC | (16h 58m 24.29s , -33d 01m 02.3s) | C | 60 | 16.5 | 29207 | 2021-08-07 20:43:00 | MASTER-IAC | (17h 10m 44.02s , -29d 13m 03.7s) | C | 60 | 16.7 | 29207 | 2021-08-07 20:43:00 | MASTER-IAC | (17h 01m 33.44s , -29d 07m 34.1s) | C | 60 | 16.6 | 29288 | 2021-08-07 20:44:20 | MASTER-IAC | (17h 02m 55.00s , -34d 53m 40.6s) | C | 60 | 16.8 | 29288 | 2021-08-07 20:44:20 | MASTER-IAC | (16h 53m 09.59s , -34d 48m 12.6s) | C | 60 | 16.7 | 29368 | 2021-08-07 20:45:40 | MASTER-IAC | (16h 55m 14.70s , -31d 06m 37.7s) | C | 60 | 17.1 | 29368 | 2021-08-07 20:45:40 | MASTER-IAC | (16h 45m 53.53s , -31d 01m 08.2s) | C | 60 | 17.0 | 29448 | 2021-08-07 20:47:00 | MASTER-IAC | (17h 21m 30.81s , -34d 54m 09.6s) | C | 60 | 18.0 | 29448 | 2021-08-07 20:47:00 | MASTER-IAC | (17h 11m 45.36s , -34d 48m 40.7s) | C | 60 | 17.3 | 29528 | 2021-08-07 20:48:21 | MASTER-IAC | (16h 53m 13.33s , -29d 12m 07.3s) | C | 60 | 17.1 | 29528 | 2021-08-07 20:48:21 | MASTER-IAC | (16h 44m 02.70s , -29d 06m 37.9s) | C | 60 | 17.3 | 29608 | 2021-08-07 20:49:41 | MASTER-IAC | (17h 09m 31.78s , -27d 17m 33.2s) | C | 60 | 17.2 | 29608 | 2021-08-07 20:49:41 | MASTER-IAC | (17h 00m 30.73s , -27d 12m 02.9s) | C | 60 | 16.9 | 29688 | 2021-08-07 20:51:00 | MASTER-IAC | (17h 30m 47.18s , -31d 07m 06.4s) | C | 60 | 17.6 | 29688 | 2021-08-07 20:51:00 | MASTER-IAC | (17h 21m 25.82s , -31d 01m 36.5s) | C | 60 | 17.1 | 29768 | 2021-08-07 20:52:20 | MASTER-IAC | (17h 08m 42.53s , -36d 49m 32.2s) | C | 60 | 17.8 | 29768 | 2021-08-07 20:52:20 | MASTER-IAC | (16h 58m 42.55s , -36d 44m 04.1s) | C | 60 | 17.0 | 29848 | 2021-08-07 20:53:40 | MASTER-IAC | (17h 28m 08.83s , -29d 13m 52.9s) | C | 60 | 17.3 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.