TITLE: GCN CIRCULAR NUMBER: 30594 SUBJECT: Fermi trigger No 649684549: Global MASTER-Net observations report DATE: 21/08/04 02:16:51 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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB210803.50 (trigger No 649684549,14h 34m 45.60s , -21d 22m 48.0s, R=1) errorbox 48997 sec after notice time and 49024 sec after trigger time at 2021-08-04 01:32:48 UT, with upper limit up to 19.5 mag. The observations began at zenith distance = 46 deg. The sun altitude is -45.3 deg. The galactic latitude b = 35 deg., longitude l = 333 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1679941 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 49114 | 2021-08-04 01:32:48 | MASTER-OAFA | (14h 25m 47.03s , -20d 18m 04.3s) | C | 180 | 19.4 | 49315 | 2021-08-04 01:36:09 | MASTER-OAFA | (14h 34m 10.87s , -20d 19m 16.2s) | C | 180 | 19.5 | 49515 | 2021-08-04 01:39:29 | MASTER-OAFA | (14h 25m 46.15s , -20d 18m 43.4s) | C | 180 | 19.4 | 49794 | 2021-08-04 01:44:08 | MASTER-OAFA | (14h 34m 13.10s , -20d 18m 57.2s) | C | 180 | 19.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.