TITLE: GCN CIRCULAR NUMBER: 30334 SUBJECT: Fermi GRB 210627B: Global MASTER-Net observations report DATE: 21/06/27 20:45:45 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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 210627B ( Fermi GBM team, GCN 30332) errorbox 126 sec after notice time and 172 sec after trigger time at 2021-06-27 18:00:12 UT, with upper limit up to 18.9 mag. The observations began at zenith distance = 39 deg. The sun altitude is -28.1 deg. The galactic latitude b = 37 deg., longitude l = 0 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1646449 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 187 | 2021-06-27 18:00:12 | MASTER-SAAO | (15h 39m 24.65s , -03d 56m 42.7s) | C | 30 | 17.7 | 242 | 2021-06-27 18:00:12 | MASTER-SAAO | (15h 39m 24.64s , -03d 56m 42.7s) | C | 140 | 18.9 | Coadd 275 | 2021-06-27 18:01:31 | MASTER-SAAO | (15h 39m 30.47s , -03d 56m 21.7s) | C | 50 | 18.2 | 350 | 2021-06-27 18:02:40 | MASTER-SAAO | (15h 39m 26.91s , -03d 54m 57.7s) | C | 60 | 18.3 | 581 | 2021-06-27 18:06:31 | MASTER-SAAO | (15h 33m 03.26s , -08d 21m 15.4s) | C | 60 | 18.5 | 733 | 2021-06-27 18:08:28 | MASTER-SAAO | (15h 39m 22.87s , -06d 00m 02.8s) | C | 130 | 18.8 | 929 | 2021-06-27 18:11:25 | MASTER-SAAO | (15h 39m 22.95s , -06d 01m 59.2s) | C | 170 | 18.7 | 1160 | 2021-06-27 18:15:10 | MASTER-SAAO | (15h 39m 26.92s , -06d 00m 21.0s) | C | 180 | 18.8 | 1396 | 2021-06-27 18:19:07 | MASTER-SAAO | (15h 39m 20.47s , -06d 00m 57.4s) | C | 180 | 18.6 | 1575 | 2021-06-27 18:23:06 | MASTER-SAAO | (15h 41m 02.44s , -08d 19m 46.4s) | C | 60 | 18.0 | 2477 | 2021-06-27 18:38:07 | MASTER-SAAO | (15h 33m 04.67s , -08d 20m 57.5s) | C | 60 | 17.2 | 2596 | 2021-06-27 18:40:06 | MASTER-SAAO | (15h 41m 04.35s , -08d 19m 36.6s) | C | 60 | 17.3 | 2715 | 2021-06-27 18:42:05 | MASTER-SAAO | (15h 29m 10.60s , -06d 25m 24.4s) | C | 60 | 17.4 | 2834 | 2021-06-27 18:44:04 | MASTER-SAAO | (15h 37m 05.80s , -06d 26m 24.8s) | C | 60 | 17.3 | 3783 | 2021-06-27 18:59:54 | MASTER-SAAO | (15h 33m 14.17s , -08d 19m 07.2s) | C | 60 | 14.6 | 3908 | 2021-06-27 19:01:58 | MASTER-SAAO | (15h 41m 15.95s , -08d 20m 58.8s) | C | 60 | 14.3 | 4027 | 2021-06-27 19:03:58 | MASTER-SAAO | (15h 29m 24.66s , -06d 25m 14.9s) | C | 60 | 14.4 | 4145 | 2021-06-27 19:05:56 | MASTER-SAAO | (15h 37m 16.64s , -06d 26m 08.9s) | C | 60 | 14.7 | 4230 | 2021-06-27 19:07:20 | MASTER-SAAO | (15h 41m 37.93s , -04d 32m 18.1s) | C | 60 | 15.5 | 4348 | 2021-06-27 19:09:19 | MASTER-SAAO | (15h 49m 29.63s , -04d 33m 34.3s) | C | 60 | 14.5 | 4467 | 2021-06-27 19:11:18 | MASTER-SAAO | (15h 44m 33.54s , -06d 25m 32.0s) | C | 60 | 14.7 | 4586 | 2021-06-27 19:13:16 | MASTER-SAAO | (15h 52m 33.05s , -06d 27m 34.6s) | C | 60 | 14.1 | 4698 | 2021-06-27 19:15:09 | MASTER-SAAO | (15h 26m 31.74s , -04d 31m 38.4s) | C | 60 | 14.9 | 4812 | 2021-06-27 19:17:03 | MASTER-SAAO | (15h 34m 28.95s , -04d 30m 54.4s) | C | 60 | 14.8 | 4931 | 2021-06-27 19:19:01 | MASTER-SAAO | (15h 29m 32.62s , -06d 25m 41.1s) | C | 60 | 14.8 | 5050 | 2021-06-27 19:21:00 | MASTER-SAAO | (15h 37m 25.99s , -06d 26m 57.7s) | C | 60 | 14.8 | 5168 | 2021-06-27 19:22:59 | MASTER-SAAO | (15h 41m 46.92s , -04d 33m 02.7s) | C | 60 | 14.4 | 5287 | 2021-06-27 19:24:57 | MASTER-SAAO | (15h 49m 42.07s , -04d 31m 27.4s) | C | 60 | 14.6 | 5406 | 2021-06-27 19:26:56 | MASTER-SAAO | (15h 44m 43.29s , -06d 26m 47.4s) | C | 60 | 14.8 | 5877 | 2021-06-27 19:34:47 | MASTER-SAAO | (15h 52m 47.68s , -06d 25m 16.9s) | C | 60 | 12.8 | 6890 | 2021-06-27 19:50:40 | MASTER-SAAO | (15h 22m 52.22s , -05d 53m 52.7s) | C | 180 | 14.8 | 7262 | 2021-06-27 19:57:52 | MASTER-SAAO | (15h 44m 57.88s , -06d 25m 27.2s) | C | 60 | 12.7 | 7360 | 2021-06-27 19:59:30 | MASTER-SAAO | (15h 52m 56.65s , -06d 24m 44.3s) | C | 60 | 14.3 | 7480 | 2021-06-27 20:01:30 | MASTER-SAAO | (15h 27m 02.62s , -04d 30m 58.8s) | C | 60 | 15.2 | 7572 | 2021-06-27 20:03:02 | MASTER-SAAO | (15h 34m 54.37s , -04d 32m 06.9s) | C | 60 | 14.4 | 8194 | 2021-06-27 20:13:24 | MASTER-SAAO | (15h 26m 42.01s , -08d 19m 28.4s) | C | 60 | 14.1 | 8716 | 2021-06-27 20:22:07 | MASTER-SAAO | (15h 32m 18.44s , -02d 35m 57.6s) | C | 60 | 12.8 | 9374 | 2021-06-27 20:33:05 | MASTER-SAAO | (15h 25m 50.78s , -08d 17m 14.7s) | C | 60 | 14.4 | 9756 | 2021-06-27 20:39:26 | MASTER-SAAO | (15h 32m 23.04s , -02d 36m 06.7s) | C | 60 | 13.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.