TITLE: GCN CIRCULAR NUMBER: 30031 SUBJECT: Fermi GRB 210516A: Global MASTER-Net observations report DATE: 21/05/17 01:30:45 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 210516A ( Fermi GBM team, GCN 30030) errorbox 259 sec after notice time and 487 sec after trigger time at 2021-05-16 23:42:54 UT, with upper limit up to 18.9 mag. The observations began at zenith distance = 46 deg. The sun altitude is -18.2 deg. MASTER-IAC robotic telescope located in Spain (IAC Teide Observatory) started inspect of the Fermi GRB 210516A errorbox 488 sec after notice time and 716 sec after trigger time at 2021-05-16 23:46:43 UT, with upper limit up to 16.6 mag. The observations began at zenith distance = 76 deg. The sun altitude is -39.6 deg. The galactic latitude b = 13 deg., longitude l = 126 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1614502 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 518 | 2021-05-16 23:42:54 | MASTER-Kislovodsk | (23h 15m 03.42s , +69d 42m 01.8s) | C | 60 | 18.4 | 518 | 2021-05-16 23:42:54 | MASTER-Kislovodsk | (23h 26m 27.46s , +69d 17m 00.5s) | C | 60 | 18.9 | 747 | 2021-05-16 23:46:43 | MASTER-IAC | (01h 13m 32.54s , +75d 01m 36.1s) | C | 60 | 16.4 | 747 | 2021-05-16 23:46:43 | MASTER-IAC | (00h 42m 15.68s , +75d 06m 55.3s) | C | 60 | 16.5 | 827 | 2021-05-16 23:48:03 | MASTER-IAC | (01h 41m 31.86s , +75d 08m 25.6s) | C | 60 | 16.5 | 827 | 2021-05-16 23:48:03 | MASTER-IAC | (02h 12m 50.85s , +75d 03m 26.4s) | C | 60 | 16.5 | 907 | 2021-05-16 23:49:23 | MASTER-IAC | (01h 30m 06.63s , +73d 13m 06.1s) | C | 60 | 16.1 | 907 | 2021-05-16 23:49:23 | MASTER-IAC | (01h 57m 55.08s , +73d 07m 53.3s) | C | 60 | 16.0 | 1231 | 2021-05-16 23:54:47 | MASTER-IAC | (01h 21m 05.39s , +71d 20m 06.8s) | C | 60 | 15.8 | 1231 | 2021-05-16 23:54:47 | MASTER-IAC | (01h 46m 10.92s , +71d 14m 39.4s) | C | 60 | 15.6 | 1311 | 2021-05-16 23:56:07 | MASTER-IAC | (00h 48m 31.14s , +77d 00m 11.2s) | C | 60 | 16.6 | 1311 | 2021-05-16 23:56:07 | MASTER-IAC | (01h 24m 15.07s , +76d 54m 58.6s) | C | 60 | 16.6 | 1391 | 2021-05-16 23:57:27 | MASTER-IAC | (01h 56m 32.02s , +77d 00m 11.0s) | C | 60 | 16.6 | 1391 | 2021-05-16 23:57:27 | MASTER-IAC | (02h 32m 15.68s , +76d 55m 25.7s) | C | 60 | 16.6 | 1483 | 2021-05-16 23:58:59 | MASTER-Kislovodsk | (23h 14m 58.41s , +69d 41m 17.7s) | C | 60 | 18.4 | 1483 | 2021-05-16 23:58:59 | MASTER-Kislovodsk | (23h 26m 24.26s , +69d 15m 49.7s) | C | 60 | 18.8 | 2445 | 2021-05-17 00:15:01 | MASTER-Kislovodsk | (23h 15m 03.39s , +69d 44m 01.9s) | C | 60 | 18.1 | 2445 | 2021-05-17 00:15:01 | MASTER-Kislovodsk | (23h 26m 33.43s , +69d 17m 56.9s) | C | 60 | 18.5 | 3166 | 2021-05-17 00:27:02 | MASTER-Kislovodsk | (02h 34m 16.56s , +81d 02m 00.0s) | C | 60 | 17.6 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.