TITLE: GCN CIRCULAR NUMBER: 23804 SUBJECT: Swift Trigger 886157: MASTER optical observation DATE: 19/01/29 10:19:25 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, P.Balanutsa, D.Vlasenko, V.Vladimirov, A.Kuznetsov, P.Balanutsa, A. Chasovnikov, D.Kuvshinov (Lomonosov Moscow State University, SAI, Physics Department), R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev (Blagoveschensk Educational State University, Blagoveschensk), A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), O. Gres, N.M. Budnev, O.Ershova, Yu.Ishmuhametov (Applied Physics Institute, Irkutsk State University), R. Podesta, C. Lopez, C.Francile, F. Podesta (Observatorio Astronomico Felix Aguilar OAFA), H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE) MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South African Astronomical Observatory, was pointed to Swift Trigger 886157 (S. D. Barthelmy et al., GCN 23800; Barthelmy et al. ATel 12436; Ttrig=2019-01-28 01:22:25 UT) 23 sec after notice time (370 sec after trigger time) at 2019-01-28 01:28:35 UT. There is no new OT, connected with GRB, with mlim=19.4 (5-sigma upper limit) on first 70s-exposition image inside Swift BAT error-box. There is no OT inside Swift XRT position (Kennea et al. ATel 12445) on first MASTER images (started at 2019-01-28 01:28:35) with mlim=19.4 and at 2019-01-29 01:44:03UT on 2 MASTER-SAAO inspect images with unfiltered mlim=20.0 (5-sigma). The galactic latitude b = -2 deg., longitude l = 352 deg. Alert observations started at zenit distance = 72 deg. The moon (48 % bright part) was 41 deg. above the horizon. The distance between moon and object is 47 deg. The sun altitude was -25.6 deg. The message may be cited.