TITLE: GCN CIRCULAR NUMBER: 28392 SUBJECT: Swift GRB 200907B: Global MASTER-Net observations report DATE: 20/09/08 01:15:06 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-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the Swift GRB 200907B ( A. P. Beardmore et al., GCN 28384) errorbox 22142 sec after notice time and 22169 sec after trigger time at 2020-09-08 01:00:40 UT, with upper limit up to 17.6 mag. The observations began at zenith distance = 59 deg. The sun altitude is -23.0 deg. MASTER-SAAO robotic telescope located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB 200907B errorbox 22375 sec after notice time and 22402 sec after trigger time at 2020-09-08 01:04:33 UT, with upper limit up to 15.9 mag. The observations began at zenith distance = 73 deg. The sun altitude is -46.6 deg. The galactic latitude b = -8 deg., longitude l = 201 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1435309 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 22260 | MASTER-Tavrida | C | 180 | 17.3 | 22461 | MASTER-Tavrida | C | 180 | 17.6 | 22493 | MASTER-SAAO | C | 180 | 15.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.