TITLE: GCN CIRCULAR NUMBER: 30612 SUBJECT: Fermi GRB 210807C: Global MASTER-Net observations report DATE: 21/08/08 03:30:32 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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 210807C ( Fermi GBM team, GCN 30609) errorbox 114 sec after notice time and 206 sec after trigger time at 2021-08-07 22:58:50 UT, with upper limit up to 18.6 mag. Observations started at twilight. The observations began at zenith distance = 64 deg. The sun altitude is -12.1 deg. MASTER-SAAO robotic telescope located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 210807C errorbox 15419 sec after notice time and 15511 sec after trigger time at 2021-08-08 03:13:56 UT, with upper limit up to 17.5 mag. The observations began at zenith distance = 81 deg. The sun altitude is -27.5 deg. The galactic latitude b = 2 deg., longitude l = 277 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1683879 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 222 | 2021-08-07 22:58:50 | MASTER-OAFA | (09h 51m 36.60s , -48d 08m 16.7s) | C | 30 | 16.4 | 285 | 2021-08-07 22:59:59 | MASTER-OAFA | (09h 32m 30.94s , -50d 38m 28.4s) | C | 20 | 16.6 | 320 | 2021-08-07 22:59:59 | MASTER-OAFA | (09h 32m 30.95s , -50d 38m 28.4s) | C | 90 | 17.3 | Coadd 615 | 2021-08-07 22:59:59 | MASTER-OAFA | (09h 32m 30.93s , -50d 38m 28.5s) | C | 680 | 18.3 | Coadd 330 | 2021-08-07 23:00:39 | MASTER-OAFA | (09h 32m 26.75s , -50d 36m 58.8s) | C | 30 | 16.8 | 384 | 2021-08-07 23:01:28 | MASTER-OAFA | (09h 32m 26.54s , -50d 38m 17.9s) | C | 40 | 17.0 | 449 | 2021-08-07 23:02:28 | MASTER-OAFA | (09h 32m 28.68s , -50d 37m 04.2s) | C | 50 | 17.1 | 524 | 2021-08-07 23:02:28 | MASTER-OAFA | (09h 32m 28.68s , -50d 37m 04.3s) | C | 200 | 17.8 | Coadd 528 | 2021-08-07 23:03:37 | MASTER-OAFA | (09h 32m 22.55s , -50d 37m 43.5s) | C | 70 | 17.3 | 622 | 2021-08-07 23:05:06 | MASTER-OAFA | (09h 32m 22.46s , -50d 36m 42.4s) | C | 80 | 17.5 | 732 | 2021-08-07 23:06:46 | MASTER-OAFA | (09h 32m 28.12s , -50d 37m 41.4s) | C | 100 | 17.7 | 877 | 2021-08-07 23:06:46 | MASTER-OAFA | (09h 32m 28.14s , -50d 37m 41.5s) | C | 390 | 18.3 | Coadd 866 | 2021-08-07 23:08:45 | MASTER-OAFA | (09h 32m 22.16s , -50d 38m 40.7s) | C | 130 | 17.9 | 1030 | 2021-08-07 23:11:14 | MASTER-OAFA | (09h 32m 29.66s , -50d 38m 09.7s) | C | 160 | 18.0 | 1220 | 2021-08-07 23:14:14 | MASTER-OAFA | (09h 32m 25.67s , -50d 37m 04.8s) | C | 180 | 18.2 | 1400 | 2021-08-07 23:14:14 | MASTER-OAFA | (09h 32m 25.67s , -50d 37m 04.8s) | C | 540 | 18.6 | Coadd 1420 | 2021-08-07 23:17:34 | MASTER-OAFA | (09h 32m 25.60s , -50d 38m 34.9s) | C | 180 | 18.2 | 1619 | 2021-08-07 23:20:53 | MASTER-OAFA | (09h 32m 28.21s , -50d 36m 47.5s) | C | 180 | 18.3 | 1819 | 2021-08-07 23:24:13 | MASTER-OAFA | (09h 32m 22.92s , -50d 37m 36.2s) | C | 180 | 18.2 | 1999 | 2021-08-07 23:24:13 | MASTER-OAFA | (09h 32m 22.92s , -50d 37m 36.2s) | C | 540 | 18.6 | Coadd 2019 | 2021-08-07 23:27:32 | MASTER-OAFA | (09h 32m 22.25s , -50d 36m 35.5s) | C | 180 | 18.3 | 2218 | 2021-08-07 23:30:52 | MASTER-OAFA | (09h 32m 28.88s , -50d 37m 34.8s) | C | 180 | 18.3 | 2417 | 2021-08-07 23:34:11 | MASTER-OAFA | (09h 32m 22.28s , -50d 38m 34.3s) | C | 180 | 18.2 | 2597 | 2021-08-07 23:34:11 | MASTER-OAFA | (09h 32m 22.29s , -50d 38m 34.3s) | C | 540 | 18.6 | Coadd 2617 | 2021-08-07 23:37:31 | MASTER-OAFA | (09h 32m 29.11s , -50d 38m 18.2s) | C | 180 | 18.2 | 2816 | 2021-08-07 23:40:50 | MASTER-OAFA | (09h 32m 25.11s , -50d 36m 58.5s) | C | 180 | 18.3 | 3016 | 2021-08-07 23:44:09 | MASTER-OAFA | (09h 32m 25.02s , -50d 38m 21.0s) | C | 180 | 18.3 | 3196 | 2021-08-07 23:44:09 | MASTER-OAFA | (09h 32m 25.02s , -50d 38m 21.0s) | C | 540 | 18.5 | Coadd 3215 | 2021-08-07 23:47:29 | MASTER-OAFA | (09h 32m 28.03s , -50d 36m 52.9s) | C | 180 | 18.2 | 3415 | 2021-08-07 23:50:49 | MASTER-OAFA | (09h 32m 21.71s , -50d 37m 32.1s) | C | 180 | 18.2 | 3614 | 2021-08-07 23:54:08 | MASTER-OAFA | (09h 32m 21.47s , -50d 36m 31.4s) | C | 180 | 18.1 | 3794 | 2021-08-07 23:54:08 | MASTER-OAFA | (09h 32m 21.47s , -50d 36m 31.5s) | C | 540 | 18.5 | Coadd 3814 | 2021-08-07 23:57:27 | MASTER-OAFA | (09h 32m 27.57s , -50d 37m 32.7s) | C | 180 | 17.9 | 4013 | 2021-08-08 00:00:47 | MASTER-OAFA | (09h 32m 20.35s , -50d 38m 40.0s) | C | 180 | 18.1 | 4212 | 2021-08-08 00:04:06 | MASTER-OAFA | (09h 32m 27.14s , -50d 38m 22.6s) | C | 180 | 18.1 | 4392 | 2021-08-08 00:04:06 | MASTER-OAFA | (09h 32m 27.14s , -50d 38m 22.6s) | C | 540 | 18.5 | Coadd 4412 | 2021-08-08 00:07:26 | MASTER-OAFA | (09h 32m 23.81s , -50d 36m 49.8s) | C | 180 | 18.1 | 4612 | 2021-08-08 00:10:46 | MASTER-OAFA | (09h 32m 23.52s , -50d 38m 37.4s) | C | 180 | 18.1 | 4811 | 2021-08-08 00:14:05 | MASTER-OAFA | (09h 32m 25.80s , -50d 36m 50.7s) | C | 180 | 18.1 | 5330 | 2021-08-08 00:22:44 | MASTER-OAFA | (09h 32m 23.46s , -50d 36m 07.4s) | C | 180 | 17.6 | 5847 | 2021-08-08 00:31:20 | MASTER-OAFA | (09h 32m 22.91s , -50d 38m 05.8s) | C | 180 | 17.5 | 6366 | 2021-08-08 00:40:00 | MASTER-OAFA | (09h 32m 21.93s , -50d 36m 57.0s) | C | 180 | 17.2 | 6884 | 2021-08-08 00:48:38 | MASTER-OAFA | (09h 32m 25.05s , -50d 36m 50.2s) | C | 180 | 17.2 | 7402 | 2021-08-08 00:57:16 | MASTER-OAFA | (09h 32m 16.96s , -50d 36m 40.0s) | C | 180 | 16.9 | 7921 | 2021-08-08 01:05:55 | MASTER-OAFA | (09h 32m 16.80s , -50d 38m 40.1s) | C | 180 | 16.7 | 8437 | 2021-08-08 01:14:31 | MASTER-OAFA | (09h 32m 17.73s , -50d 36m 54.2s) | C | 180 | 16.6 | 8956 | 2021-08-08 01:23:10 | MASTER-OAFA | (09h 32m 20.07s , -50d 36m 39.2s) | C | 180 | 16.1 | 9475 | 2021-08-08 01:31:49 | MASTER-OAFA | (09h 32m 10.94s , -50d 36m 17.5s) | C | 180 | 14.0 | 15602 | 2021-08-08 03:13:56 | MASTER-SAAO | (09h 34m 22.59s , -51d 21m 56.9s) | C | 180 | 17.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.