TITLE: GCN CIRCULAR NUMBER: 30906 SUBJECT: Swift GRB211001.03: Global MASTER-Net observations report DATE: 21/10/01 01:58:35 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-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) was pointed to the Swift GRB211001.03 (trigger No 1076121,04h 45m 52.80s , +12d 02m 24.0s, R=0.05) errorbox 41 sec after trigger time at 2021-10-01 00:44:01 UT, with upper limit up to 19.1 mag. The observations began at zenith distance = 35 deg. The sun altitude is -31.3 deg. The galactic latitude b = -20 deg., longitude l = 187 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1738591 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 47 | MASTER-Tavrida | P\ | 10 | 14.7 | 76 | MASTER-Tavrida | P\ | 10 | 14.8 | 110 | MASTER-Tavrida | P\ | 20 | 15.1 | 154 | MASTER-Tavrida | P\ | 30 | 14.8 | 209 | MASTER-Tavrida | P\ | 40 | 15.2 | 273 | MASTER-Tavrida | P\ | 50 | 15.8 | 347 | MASTER-Tavrida | P\ | 60 | 15.9 | 436 | MASTER-Tavrida | P\ | 80 | 15.9 | 545 | MASTER-Tavrida | P\ | 100 | 15.9 | 674 | MASTER-Tavrida | P\ | 120 | 16.0 | 1099 | MASTER-Tavrida | C | 180 | 18.4 | 1298 | MASTER-Tavrida | C | 180 | 18.5 | 1566 | MASTER-Tavrida | C | 180 | 18.6 | 1765 | MASTER-Tavrida | C | 180 | 18.7 | 1964 | MASTER-Tavrida | C | 180 | 18.8 | 2163 | MASTER-Tavrida | C | 180 | 18.9 | 2362 | MASTER-Tavrida | C | 180 | 18.9 | 2561 | MASTER-Tavrida | C | 180 | 19.0 | 2760 | MASTER-Tavrida | C | 180 | 19.1 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.