TITLE: GCN CIRCULAR NUMBER: 28264 SUBJECT: Swift GRB 200819A: Global MASTER-Net observations report DATE: 20/08/19 16:58:19 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), H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), 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-Tunka robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the Swift GRB 200819A ( S. Dichiara et al., GCN 28263) errorbox 80 sec after notice time and 149 sec after trigger time at 2020-08-19 15:46:22 UT, with upper limit up to 17.7 mag. The observations began at zenith distance = 39 deg. The sun altitude is -23.8 deg. The galactic latitude b = 1 deg., longitude l = 127 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1422693 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 165 | MASTER-Tunka | P| | 30 | 16.3 | 465 | MASTER-Tunka | P| | 630 | 17.7 | Coadd 219 | MASTER-Tunka | P| | 40 | 16.5 | 284 | MASTER-Tunka | P| | 50 | 16.7 | 358 | MASTER-Tunka | P| | 60 | 16.9 | 448 | MASTER-Tunka | P| | 80 | 17.0 | 557 | MASTER-Tunka | P| | 100 | 16.8 | 687 | MASTER-Tunka | P| | 120 | 16.6 | 841 | MASTER-Tunka | P| | 150 | 16.1 | 1026 | MASTER-Tunka | P| | 180 | 16.1 | The observation and reduction will continue. The message may be cited.