TITLE: GCN CIRCULAR NUMBER: 25518 SUBJECT: Swift GRB190828.54 Global MASTER-Net observations report DATE: 19/08/28 13:55:10 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 (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 GRB190828.54 (trigger No 922808,16h 47m 16.320s , +27d 14m 13.20s, R=0.05) errorbox 648 sec after notice time and 674 sec after trigger time at 2019-08-28 13:11:13 UT, with upper limit up to 19.4 mag. Observations started at twilight. The observations began at zenit distance = 31 deg. The sun altitude is -10.6 deg. The galactic latitude b = -60 deg., longitude l = 98 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1118074 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 734 | MASTER-Tunka | P| | 120 | 18.4 | 734 | MASTER-Tunka | P- | 120 | 16.8 | 1189 | MASTER-Tunka | P| | 180 | 19.3 | 1189 | MASTER-Tunka | P- | 180 | 17.4 | 1491 | MASTER-Tunka | P| | 180 | 19.4 | 1491 | MASTER-Tunka | P- | 180 | 17.8 | The observation and reduction will continue. The message may be cited.