TITLE: GCN CIRCULAR NUMBER: 30149 SUBJECT: MAXI GRB210607.82: Global MASTER-Net observations report DATE: 21/06/07 23:17:07 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-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the MAXI GRB210607.82 (trigger No 372671890,17h 33m 42.24s , -22d 37m 22.8s, R=1) errorbox 46 sec after notice time and 12291 sec after trigger time at 2021-06-07 23:07:59 UT, with upper limit up to 17.4 mag. The observations began at zenith distance = 68 deg. The sun altitude is -20.3 deg. MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the MAXI GRB210607.82 errorbox 97 sec after notice time and 12342 sec after trigger time at 2021-06-07 23:08:50 UT, with upper limit up to 17.4 mag. The observations began at zenith distance = 68 deg. The sun altitude is -18.7 deg. The galactic latitude b = 5 deg., longitude l = 4 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1630751 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 12381 | 2021-06-07 23:07:59 | MASTER-Tavrida | (17h 30m 36.86s , -22d 29m 42.1s) | C | 180 | 17.4 | 12433 | 2021-06-07 23:08:50 | MASTER-Kislovodsk | (17h 34m 32.26s , -22d 10m 55.8s) | P| | 180 | 17.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.