TITLE: GCN CIRCULAR NUMBER: 30556 SUBJECT: Fermi trigger No 649313854: Global MASTER-Net observations report DATE: 21/07/30 18:30:17 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 Fermi GRB210730.21 (trigger No 649313854,09h 54m 55.20s , +73d 06m 00.0s, R=2.61) errorbox 47717 sec after notice time and 47748 sec after trigger time at 2021-07-30 18:13:17 UT, with upper limit up to 17.8 mag. Observations started at twilight. The observations began at zenith distance = 52 deg. The sun altitude is -10.5 deg. The galactic latitude b = 39 deg., longitude l = 138 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1675890 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 47778 | 2021-07-30 18:13:17 | MASTER-Tavrida | (09h 49m 09.94s , +74d 53m 29.9s) | C | 60 | 16.5 | 47857 | 2021-07-30 18:14:36 | MASTER-Tavrida | (10h 20m 26.47s , +74d 55m 07.8s) | C | 60 | 17.2 | 47937 | 2021-07-30 18:15:55 | MASTER-Tavrida | (09h 26m 58.28s , +71d 05m 48.6s) | C | 60 | 16.8 | 48016 | 2021-07-30 18:17:14 | MASTER-Tavrida | (09h 52m 04.86s , +71d 06m 12.7s) | C | 60 | 17.0 | 48095 | 2021-07-30 18:18:34 | MASTER-Tavrida | (10h 29m 25.43s , +73d 03m 08.3s) | C | 60 | 17.6 | 48174 | 2021-07-30 18:19:53 | MASTER-Tavrida | (10h 57m 20.24s , +73d 06m 34.7s) | C | 60 | 17.8 | 48254 | 2021-07-30 18:21:12 | MASTER-Tavrida | (10h 06m 04.25s , +76d 46m 15.8s) | C | 60 | 17.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.