TITLE: GCN CIRCULAR NUMBER: 25800 SUBJECT: Fermi trigger No 590777160: Global MASTER-Net observations report DATE: 19/09/21 17:31:52 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 GRB190921.7 (trigger No 590777160,22h 33m 31.200s , -63d 25m 12.00s, R=5.38) errorbox 1740 sec after notice time and 1835 sec after trigger time at 2019-09-21 17:16:30 UT, with upper limit up to 14.6 mag. Observations started at twilight. The observations began at zenit distance = 47 deg. The sun altitude is -9.8 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=1144338 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 1865 | 2019-09-21 17:16:30 | MASTER-SAAO | (22h 23m 28.775s , -64d 03m 22.03s) | C | 60 | 14.2 | 1961 | 2019-09-21 17:18:06 | MASTER-SAAO | (22h 34m 32.658s , -62d 03m 56.81s) | C | 60 | 14.6 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.