TITLE: GCN CIRCULAR NUMBER: 29992 SUBJECT: Fermi GRB 210511B: Global MASTER-Net observations report DATE: 21/05/11 18:31:20 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-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 210511B ( Fermi GBM team, GCN 29988) errorbox 24287 sec after notice time and 24402 sec after trigger time at 2021-05-11 18:13:21 UT, with upper limit up to 18.0 mag. The observations began at zenith distance = 68 deg. The sun altitude is -17.1 deg. The galactic latitude b = 10 deg., longitude l = 99 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1611119 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 24492 | 2021-05-11 18:13:21 | MASTER-Kislovodsk | (21h 04m 20.43s , +61d 44m 35.3s) | C | 180 | 17.6 | 24493 | 2021-05-11 18:13:21 | MASTER-Kislovodsk | (21h 04m 10.88s , +61d 20m 40.1s) | C | 180 | 18.0 | 24693 | 2021-05-11 18:16:41 | MASTER-Kislovodsk | (21h 04m 27.56s , +61d 43m 35.1s) | C | 180 | 17.5 | 24693 | 2021-05-11 18:16:41 | MASTER-Kislovodsk | (21h 04m 18.29s , +61d 19m 37.6s) | C | 180 | 18.0 | 24893 | 2021-05-11 18:20:02 | MASTER-Kislovodsk | (20h 54m 20.98s , +62d 42m 45.4s) | C | 180 | 17.4 | 24893 | 2021-05-11 18:20:02 | MASTER-Kislovodsk | (20h 54m 12.62s , +62d 18m 48.3s) | C | 180 | 17.9 | 25093 | 2021-05-11 18:23:22 | MASTER-Kislovodsk | (20h 54m 27.35s , +62d 43m 01.4s) | C | 180 | 17.4 | 25093 | 2021-05-11 18:23:22 | MASTER-Kislovodsk | (20h 54m 19.40s , +62d 19m 03.9s) | C | 180 | 17.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.