TITLE: GCN CIRCULAR NUMBER: 30435 SUBJECT: MAXI GRB210709.93: Global MASTER-Net observations report DATE: 21/07/10 01:17:08 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 GRB210709.93 (trigger No 404728808,18h 49m 35.04s , -23d 47m 09.6s, R=1) errorbox 22 sec after notice time and 9031 sec after trigger time at 2021-07-10 00:43:14 UT, with upper limit up to 17.2 mag. The observations began at zenith distance = 33 deg. The sun altitude is -61.9 deg. MASTER-OAFA robotic telescope located in Argentina (OAFA observatory of San Juan National University) started inspect of the MAXI GRB210709.93 errorbox 65 sec after notice time and 9074 sec after trigger time at 2021-07-10 00:43:57 UT, with upper limit up to 17.8 mag. The observations began at zenith distance = 45 deg. The sun altitude is -37.1 deg. MASTER-IAC robotic telescope located in Spain (IAC Teide Observatory) started inspect of the MAXI GRB210709.93 errorbox 221 sec after notice time and 9230 sec after trigger time at 2021-07-10 00:46:33 UT, with upper limit up to 17.9 mag. The observations began at zenith distance = 52 deg. The sun altitude is -39.5 deg. The galactic latitude b = -11 deg., longitude l = 12 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1656741 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 9122 | 2021-07-10 00:43:14 | MASTER-SAAO | (18h 49m 20.18s , -23d 49m 21.2s) | P\ | 180 | 16.8 | 9165 | 2021-07-10 00:43:57 | MASTER-OAFA | (18h 45m 44.59s , -24d 28m 20.5s) | C | 180 | 17.8 | 9320 | 2021-07-10 00:46:33 | MASTER-IAC | (18h 48m 21.21s , -23d 48m 23.2s) | P| | 180 | 17.7 | 9320 | 2021-07-10 00:46:33 | MASTER-IAC | (18h 47m 31.50s , -23d 42m 56.0s) | P- | 180 | 17.6 | 9321 | 2021-07-10 00:46:34 | MASTER-SAAO | (18h 49m 26.11s , -23d 50m 11.5s) | P\ | 180 | 17.0 | 9364 | 2021-07-10 00:47:17 | MASTER-OAFA | (18h 45m 50.17s , -24d 29m 19.2s) | C | 180 | 17.8 | 9520 | 2021-07-10 00:49:53 | MASTER-IAC | (18h 48m 19.96s , -23d 47m 27.2s) | P| | 180 | 17.9 | 9520 | 2021-07-10 00:49:53 | MASTER-IAC | (18h 47m 30.25s , -23d 41m 59.2s) | P- | 180 | 17.7 | 9520 | 2021-07-10 00:49:53 | MASTER-SAAO | (18h 49m 20.57s , -23d 51m 03.3s) | P\ | 180 | 16.9 | 9564 | 2021-07-10 00:50:36 | MASTER-OAFA | (18h 45m 45.28s , -24d 30m 17.7s) | C | 180 | 17.8 | 9720 | 2021-07-10 00:53:12 | MASTER-SAAO | (18h 49m 25.49s , -23d 50m 55.4s) | P\ | 180 | 17.2 | 9722 | 2021-07-10 00:53:14 | MASTER-IAC | (18h 48m 27.11s , -23d 48m 29.4s) | P| | 180 | 17.9 | 9722 | 2021-07-10 00:53:14 | MASTER-IAC | (18h 47m 37.30s , -23d 43m 00.9s) | P- | 180 | 17.7 | 9763 | 2021-07-10 00:53:55 | MASTER-OAFA | (18h 45m 50.32s , -24d 30m 15.0s) | C | 180 | 17.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.