TITLE: GCN CIRCULAR NUMBER: 29285 SUBJECT: MAXI GRB210110.64: Global MASTER-Net observations report DATE: 21/01/10 19:51:09 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 MAXI GRB210110.64 (trigger No 224516204,11h 30m 38.40s , -41d 30m 36.0s, R=1) errorbox 14698 sec after notice time and 15987 sec after trigger time at 2021-01-10 19:41:11 UT, with upper limit up to 17.4 mag. The observations began at zenith distance = 80 deg. The sun altitude is -20.2 deg. The galactic latitude b = 19 deg., longitude l = 288 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1522841 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 16077 | 2021-01-10 19:41:11 | MASTER-SAAO | (11h 25m 31.35s , -41d 24m 21.0s) | C | 180 | 17.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.