TITLE: GCN CIRCULAR NUMBER: 33092 SUBJECT: Fermi GRB 221221A: Global MASTER-Net observations report DATE: 22/12/22 01:45:20 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin (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 (Irkutsk State University, API), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational State University) MASTER-Tunka robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 221221A ( Fermi GBM team, GCN 33091) errorbox 889 sec after notice time and 900 sec after trigger time at 2022-12-21 22:54:31 UT, with upper limit up to 19.4 mag. The observations began at zenith distance = 50 deg. The sun altitude is -19.6 deg. The galactic latitude b = 16 deg., longitude l = 149 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2186194 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 931 | 2022-12-21 22:54:31 | MASTER-Tunka | (05h 13m 04.10s , +62d 00m 46.8s) | C | 60 | 19.1 | 931 | 2022-12-21 22:54:31 | MASTER-Tunka | (05h 33m 09.63s , +62d 02m 27.4s) | C | 60 | 19.0 | 1021 | 2022-12-21 22:56:01 | MASTER-Tunka | (04h 59m 40.57s , +63d 52m 33.3s) | C | 60 | 19.4 | 1021 | 2022-12-21 22:56:01 | MASTER-Tunka | (05h 21m 04.98s , +63d 54m 10.7s) | C | 60 | 19.4 | 1112 | 2022-12-21 22:57:32 | MASTER-Tunka | (05h 34m 02.96s , +63d 54m 26.5s) | C | 60 | 19.0 | 1206 | 2022-12-21 22:59:06 | MASTER-Tunka | (05h 21m 31.91s , +65d 47m 31.1s) | C | 60 | 19.3 | 1206 | 2022-12-21 22:59:06 | MASTER-Tunka | (05h 44m 33.68s , +65d 49m 16.4s) | C | 60 | 19.4 | 1296 | 2022-12-21 23:00:36 | MASTER-Tunka | (05h 45m 26.07s , +62d 03m 08.6s) | C | 60 | 19.0 | 1296 | 2022-12-21 23:00:36 | MASTER-Tunka | (06h 05m 34.83s , +62d 04m 53.5s) | C | 60 | 19.1 | 1397 | 2022-12-21 23:02:17 | MASTER-Tunka | (05h 25m 24.08s , +60d 05m 34.7s) | C | 60 | 18.9 | 1397 | 2022-12-21 23:02:17 | MASTER-Tunka | (05h 44m 17.59s , +60d 07m 10.0s) | C | 60 | 18.9 | 1488 | 2022-12-21 23:03:48 | MASTER-Tunka | (05h 32m 12.18s , +67d 42m 58.9s) | C | 60 | 19.1 | 1578 | 2022-12-21 23:05:18 | MASTER-Tunka | (05h 07m 27.77s , +65d 46m 10.6s) | C | 60 | 19.4 | 1669 | 2022-12-21 23:06:49 | MASTER-Tunka | (05h 13m 47.63s , +60d 05m 33.9s) | C | 60 | 18.5 | 1759 | 2022-12-21 23:08:19 | MASTER-Tunka | (05h 00m 55.35s , +61d 57m 06.8s) | C | 60 | 18.7 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.