TITLE: GCN CIRCULAR NUMBER: 29966 SUBJECT: Fermi GRB 210507A: Global MASTER-Net observations report DATE: 21/05/07 23:47:04 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-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 GRB 210507A ( Fermi GBM team, GCN 29963) errorbox 13215 sec after notice time and 13259 sec after trigger time at 2021-05-07 22:21:37 UT, with upper limit up to 16.4 mag. The observations began at zenith distance = 64 deg. The sun altitude is -28.2 deg. The galactic latitude b = -7 deg., longitude l = 28 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1608957 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 13289 | 2021-05-07 22:21:37 | MASTER-Tavrida | (18h 39m 42.53s , -05d 50m 35.3s) | C | 60 | 16.2 | 13369 | 2021-05-07 22:22:56 | MASTER-Tavrida | (18h 47m 41.85s , -05d 49m 21.3s) | C | 60 | 15.5 | 13448 | 2021-05-07 22:24:16 | MASTER-Tavrida | (19h 08m 22.09s , -03d 50m 07.2s) | C | 60 | 14.7 | 14144 | 2021-05-07 22:35:52 | MASTER-Tavrida | (18h 50m 06.67s , -11d 49m 27.8s) | C | 60 | 14.6 | 14303 | 2021-05-07 22:38:31 | MASTER-Tavrida | (18h 39m 36.28s , -05d 51m 08.3s) | C | 60 | 16.2 | 14383 | 2021-05-07 22:39:50 | MASTER-Tavrida | (18h 47m 43.48s , -05d 51m 16.2s) | C | 60 | 15.3 | 14462 | 2021-05-07 22:41:10 | MASTER-Tavrida | (19h 08m 18.97s , -03d 50m 08.6s) | C | 60 | 16.3 | 14542 | 2021-05-07 22:42:29 | MASTER-Tavrida | (19h 16m 19.74s , -03d 52m 03.0s) | C | 60 | 15.4 | 14780 | 2021-05-07 22:46:27 | MASTER-Tavrida | (18h 50m 17.91s , -01d 50m 21.3s) | C | 60 | 16.0 | 14859 | 2021-05-07 22:47:47 | MASTER-Tavrida | (18h 58m 10.12s , -01d 51m 34.0s) | C | 60 | 15.8 | 14939 | 2021-05-07 22:49:06 | MASTER-Tavrida | (18h 58m 23.62s , -11d 51m 16.5s) | C | 60 | 15.7 | 15018 | 2021-05-07 22:50:25 | MASTER-Tavrida | (18h 42m 01.11s , -11d 49m 36.3s) | C | 60 | 16.1 | 15097 | 2021-05-07 22:51:45 | MASTER-Tavrida | (18h 50m 11.34s , -11d 51m 18.5s) | C | 60 | 15.7 | 15176 | 2021-05-07 22:53:04 | MASTER-Tavrida | (19h 06m 35.40s , -11d 50m 01.0s) | C | 60 | 15.2 | 15256 | 2021-05-07 22:54:23 | MASTER-Tavrida | (18h 39m 36.53s , -05d 50m 17.3s) | C | 60 | 15.9 | 15335 | 2021-05-07 22:55:43 | MASTER-Tavrida | (18h 47m 39.14s , -05d 49m 27.6s) | C | 60 | 15.7 | 15414 | 2021-05-07 22:57:02 | MASTER-Tavrida | (19h 08m 21.68s , -03d 50m 54.0s) | C | 60 | 16.4 | 15494 | 2021-05-07 22:58:21 | MASTER-Tavrida | (19h 16m 17.82s , -03d 52m 06.1s) | C | 60 | 16.2 | 15573 | 2021-05-07 22:59:40 | MASTER-Tavrida | (19h 16m 48.78s , -07d 51m 55.6s) | C | 60 | 14.8 | 16375 | 2021-05-07 23:13:02 | MASTER-Tavrida | (19h 24m 47.14s , -07d 52m 30.5s) | C | 60 | 15.3 | 16454 | 2021-05-07 23:14:21 | MASTER-Tavrida | (18h 50m 17.29s , -01d 51m 11.9s) | C | 60 | 16.0 | 16533 | 2021-05-07 23:15:41 | MASTER-Tavrida | (18h 58m 14.20s , -01d 50m 10.2s) | C | 60 | 15.4 | 16692 | 2021-05-07 23:18:20 | MASTER-Tavrida | (18h 50m 14.77s , -11d 50m 29.4s) | C | 60 | 13.1 | 16772 | 2021-05-07 23:19:39 | MASTER-Tavrida | (19h 06m 11.36s , -01d 49m 57.6s) | C | 60 | 14.4 | 16988 | 2021-05-07 23:23:15 | MASTER-Tavrida | (19h 14m 13.03s , -01d 50m 13.9s) | C | 60 | 13.6 | 17067 | 2021-05-07 23:24:35 | MASTER-Tavrida | (18h 42m 39.27s , -09d 50m 57.9s) | C | 60 | 14.0 | 17286 | 2021-05-07 23:28:13 | MASTER-Tavrida | (19h 14m 49.76s , -11d 51m 33.2s) | C | 60 | 12.4 | 17365 | 2021-05-07 23:29:33 | MASTER-Tavrida | (18h 44m 14.43s , -03d 51m 43.4s) | C | 60 | 15.2 | 17603 | 2021-05-07 23:33:31 | MASTER-Tavrida | (18h 50m 17.03s , -01d 49m 55.9s) | C | 60 | 14.4 | 17682 | 2021-05-07 23:34:50 | MASTER-Tavrida | (18h 58m 12.28s , -01d 50m 56.9s) | C | 60 | 14.6 | 17841 | 2021-05-07 23:37:29 | MASTER-Tavrida | (19h 06m 18.59s , -01d 51m 08.0s) | C | 60 | 14.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.