TITLE: GCN CIRCULAR NUMBER: 30951 SUBJECT: Fermi trigger No 656506979: Global MASTER-Net observations report DATE: 21/10/21 11:15:23 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> 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-Tunka robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB211021.46 (trigger No 656506979,01h 51m 52.80s , +27d 04m 12.0s, R=5.45) errorbox 60 sec after notice time and 89 sec after trigger time at 2021-10-21 11:04:24 UT, with upper limit up to 15.1 mag. Observations started at twilight. The observations began at zenith distance = 68 deg. The sun altitude is -10.4 deg. The galactic latitude b = -33 deg., longitude l = 140 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1760013 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 91 | 2021-10-21 11:04:24 | MASTER-Tunka | (01h 42m 42.84s , +26d 26m 06.9s) | C | 1 | 15.0 | 96 | 2021-10-21 11:04:29 | MASTER-Tunka | (01h 42m 42.68s , +26d 26m 05.3s) | C | 1 | 15.1 | 103 | 2021-10-21 11:04:36 | MASTER-Tunka | (01h 42m 42.69s , +26d 26m 04.6s) | C | 1 | 14.4 | 103 | 2021-10-21 11:04:36 | MASTER-Tunka | (01h 45m 02.37s , +25d 16m 04.0s) | C | 1 | 12.2 | 109 | 2021-10-21 11:04:42 | MASTER-Tunka | (01h 42m 42.67s , +26d 26m 05.3s) | C | 1 | 14.6 | 116 | 2021-10-21 11:04:49 | MASTER-Tunka | (01h 42m 42.67s , +26d 26m 04.6s) | C | 1 | 14.7 | 123 | 2021-10-21 11:04:56 | MASTER-Tunka | (01h 42m 42.72s , +26d 26m 04.7s) | C | 1 | 14.6 | 133 | 2021-10-21 11:05:06 | MASTER-Tunka | (01h 42m 42.68s , +26d 26m 05.9s) | C | 1 | 14.9 | 138 | 2021-10-21 11:05:11 | MASTER-Tunka | (01h 42m 42.75s , +26d 26m 04.8s) | C | 1 | 15.1 | 144 | 2021-10-21 11:05:17 | MASTER-Tunka | (01h 42m 42.81s , +26d 26m 04.8s) | C | 1 | 14.7 | 151 | 2021-10-21 11:05:24 | MASTER-Tunka | (01h 42m 42.72s , +26d 26m 04.8s) | C | 1 | 14.8 | 158 | 2021-10-21 11:05:31 | MASTER-Tunka | (01h 42m 42.79s , +26d 26m 04.1s) | C | 1 | 14.7 | 164 | 2021-10-21 11:05:37 | MASTER-Tunka | (01h 42m 42.69s , +26d 26m 04.9s) | C | 1 | 14.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.