TITLE: GCN CIRCULAR NUMBER: 30939 SUBJECT: Swift GRB211017.99: Global MASTER-Net observations report DATE: 21/10/18 19:25:07 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-IAC robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Spain (IAC Teide Observatory) was pointed to the Swift GRB211017.99 (trigger No 1079966,16h 19m 54.86s , -15d 50m 31.6s, R=0.05) errorbox 69997 sec after notice time and 70095 sec after trigger time at 2021-10-18 19:13:31 UT, with upper limit up to 16.2 mag. Observations started at twilight. The observations began at zenith distance = 69 deg. The sun altitude is -10.2 deg. The galactic latitude b = 23 deg., longitude l = 359 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1755387 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 70186 | MASTER-IAC | C | 180 | 14.7 | 70325 | MASTER-IAC | C | 60 | 16.2 | 70325 | MASTER-IAC | C | 60 | 15.1 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.