TITLE: GCN CIRCULAR NUMBER: 30706 SUBJECT: Fermi GRB 210824A: Global MASTER-Net observations report DATE: 21/08/24 17:01:04 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-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 GRB 210824A ( Fermi GBM team, GCN 30699) errorbox 45625 sec after notice time and 45651 sec after trigger time at 2021-08-24 16:50:54 UT, with upper limit up to 17.2 mag. Observations started at twilight. The observations began at zenith distance = 46 deg. The sun altitude is -7.8 deg. The galactic latitude b = 46 deg., longitude l = 19 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1698440 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 45682 | 2021-08-24 16:50:54 | MASTER-SAAO | (15h 30m 37.82s , +12d 36m 58.0s) | C | 60 | 16.0 | 45762 | 2021-08-24 16:52:14 | MASTER-SAAO | (15h 38m 47.90s , +12d 35m 22.7s) | C | 60 | 16.6 | 45841 | 2021-08-24 16:53:34 | MASTER-SAAO | (15h 24m 16.66s , +10d 42m 42.8s) | C | 60 | 17.0 | 45921 | 2021-08-24 16:54:54 | MASTER-SAAO | (15h 32m 23.86s , +10d 43m 21.8s) | C | 60 | 17.2 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.