TITLE: GCN CIRCULAR NUMBER: 29631 SUBJECT: Fermi trigger No 636926765: Global MASTER-Net observations report DATE: 21/03/09 02:45:10 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, 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 GRB210308.84 (trigger No 636926765,23h 21m 55.20s , -53d 33m 00.0s, R=9.2) errorbox 15354 sec after notice time and 21707 sec after trigger time at 2021-03-09 02:07:47 UT, with upper limit up to 14.5 mag. The observations began at zenith distance = 75 deg. The sun altitude is -30.4 deg. The galactic latitude b = -59 deg., longitude l = 329 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1564072 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 21737 | 2021-03-09 02:07:47 | MASTER-SAAO | (22h 35m 11.36s , -61d 04m 45.8s) | C | 60 | 14.1 | 21817 | 2021-03-09 02:09:07 | MASTER-SAAO | (22h 16m 21.84s , -59d 07m 06.4s) | C | 60 | 14.5 | 22056 | 2021-03-09 02:13:06 | MASTER-SAAO | (22h 58m 28.88s , -63d 04m 39.8s) | C | 60 | 13.6 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.