TITLE: GCN CIRCULAR NUMBER: 25428 SUBJECT: Fermi trigger No 588100239 Global MASTER-Net observations report DATE: 19/08/21 17:31:15 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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB190821.72 (trigger No 588100239, 16h 55m 57.60s , -38d 37m 12.00s, R=7.21) errorbox 10 sec after trigger time at 2019-08-21 17:10:44 UT, with upper limit up to 17.3 mag. Observations started at twilight. The observations began at zenit distance = 3 deg. The sun altitude is -12.4 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=1111565 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 15 | 2019-08-21 17:10:44 | MASTER-SAAO | ( 16h 41m 19.25s , -33d 57m 12.76s) | P\ | 10 | 16.3 | 42 | 2019-08-21 17:11:10 | MASTER-SAAO | ( 16h 40m 18.01s , -33d 57m 11.66s) | P\ | 10 | 16.4 | 67 | 2019-08-21 17:11:10 | MASTER-SAAO | ( 16h 40m 18.01s , -33d 57m 11.62s) | P\ | 60 | 17.3 | Coadd 73 | 2019-08-21 17:11:36 | MASTER-SAAO | ( 16h 40m 18.03s , -33d 57m 11.45s) | P\ | 20 | 16.9 | The observation and reduction will continue. The message may be cited.