TITLE: GCN CIRCULAR NUMBER: 26555 SUBJECT: GRB 191221B: MASTER VWFC OT yearly detection DATE: 19/12/22 14:31:51 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(Lomonosov Moscow State University, SAI, Physics Department), D. Buckley(South African Astronomical Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), R. Podesta, C.Lopez, F. Podesta, C.Francile(Observatorio Astronomico Felix Aguilar OAFA), H.Levato(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State University) We found first image with error box at 2019-12-21 20:40:15 (62 sec after trigger time). MASTER-OAFA Very Wide Field Camera detected OT in Swift GRB 191221B (Laha et al GCN 26534; Lipunov et al., GCN 26537; Kuin, GCN 26538; Gokuldass et al., GCN 26551; Vielfaure et al., GCN 26553;) error-box at coordinates at 2019-12-21 20:41:35 UT (142 s after trigger time). with m_OT~10.5 mag. The observation and reduction will be continued. The message may be cited.