TITLE: GCN CIRCULAR NUMBER: 30811 SUBJECT: Fermi trigger No 653054042: Global MASTER-Net observations report DATE: 21/09/11 17:16:03 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) started inspect of the Fermi GRB210911.50 (trigger No 653054042,18h 33m 36.00s , +05d 55m 01.2s, R=27.42) errorbox 18426 sec after notice time and 18466 sec after trigger time at 2021-09-11 17:01:43 UT, with upper limit up to 16.5 mag. Observations started at twilight. The observations began at zenith distance = 29 deg. The sun altitude is -11.5 deg. The galactic latitude b = 6 deg., longitude l = 37 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1717465 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 18471 | 2021-09-11 17:01:43 | MASTER-Tavrida | (19h 22m 56.19s , +15d 57m 57.5s) | C | 10 | 12.9 | 18500 | 2021-09-11 17:02:12 | MASTER-Tavrida | (19h 22m 52.77s , +15d 59m 30.8s) | C | 10 | 13.0 | 18534 | 2021-09-11 17:02:41 | MASTER-Tavrida | (19h 30m 01.45s , +15d 40m 57.4s) | P\ | 20 | 12.5 | 18574 | 2021-09-11 17:03:20 | MASTER-Tavrida | (19h 30m 04.18s , +15d 42m 26.2s) | P\ | 20 | 12.3 | 18669 | 2021-09-11 17:04:46 | MASTER-Tavrida | (19h 29m 59.60s , +15d 42m 33.7s) | P\ | 40 | 15.4 | 18729 | 2021-09-11 17:04:46 | MASTER-Tavrida | (19h 29m 59.61s , +15d 42m 33.6s) | P\ | 160 | 16.3 | Coadd 18733 | 2021-09-11 17:05:45 | MASTER-Tavrida | (19h 30m 04.14s , +15d 41m 30.9s) | P\ | 50 | 15.7 | 18812 | 2021-09-11 17:06:54 | MASTER-Tavrida | (19h 29m 59.44s , +15d 40m 26.8s) | P\ | 70 | 16.3 | 18912 | 2021-09-11 17:08:23 | MASTER-Tavrida | (19h 30m 06.28s , +15d 40m 44.3s) | P\ | 90 | 16.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.