TITLE: GCN CIRCULAR NUMBER: 30606 SUBJECT: Swift GRB210807.79: Global MASTER-Net observations report DATE: 21/08/07 19:41:16 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 GRB210807.79 (trigger No 1064380,16h 20m 27.48s , -15d 56m 11.4s, R=0.05) errorbox 74 sec after notice time and 155 sec after trigger time at 2021-08-07 18:54:15 UT, with upper limit up to 16.8 mag. The observations began at zenith distance = 66 deg. The sun altitude is -17.8 deg. The galactic latitude b = 23 deg., longitude l = 359 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1683622 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 170 | MASTER-Tavrida | P\ | 30 | 13.9 | 225 | MASTER-Tavrida | P\ | 40 | 14.0 | 289 | MASTER-Tavrida | P\ | 50 | 14.7 | 363 | MASTER-Tavrida | P\ | 60 | 14.4 | 452 | MASTER-Tavrida | P\ | 80 | 14.7 | 561 | MASTER-Tavrida | P\ | 100 | 14.7 | 929 | MASTER-Tavrida | C | 180 | 16.8 | 1366 | MASTER-Tavrida | C | 180 | 16.1 | 1802 | MASTER-Tavrida | C | 180 | 16.2 | 2541 | MASTER-Tavrida | C | 180 | 16.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.