TITLE: GCN CIRCULAR NUMBER: 18820 SUBJECT: GRB 160104A: MASTER early OT detection DATE: 16/01/04 14:18:39 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.Yurkov, Yu.Sergienko, A.Gabovich, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk O. Gress, K. Ivanov, N.M. Budnev, V.A. Poleshchuk, S.A. Yazev Irkutsk State University V. Lipunov, E. Gorbovskoy, N.Tyurina, D. Vlasenko, V.Kornilov, P.Balanutsa, A.Kuznetsov, D. Vlasenko Lomonosov Moscow State University, Sternberg Astronomical Institute R. Rebolo, M. Serra-Ricart, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias report on behalf of the MASTER Team: MASTER-Amur robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Blagoveschensk was pointed to the GRB160104A (Melandri et al., GCN 18815) 10 sec after notice time and 32 sec after trigger time at 2016-01-04 11:24:46 UT. On our first (10s exposure) set we have found optical transient with 17.0+/-0.3 unfiltered magnitude at LCOGT-FTN and MITSuME Akeno position (Guidorzi et al., GCN 18816; Saito et al., GCN 18817) The 5-sigma upper limit has been about 17.3 mag MASTER-Tunka robotic telescope (MASTER-Net: http://observ.pereplet.ru) located near Bykal lake was pointed to the GRB160104A 66 sec after trigger time at 2016-01-04 11:25:20 UT. On our first (10s exposure) set we have found marginally optical transient ~17 unfiltered magnitude. The 5-sigma upper limit has been about 17.2mag The reduction is continuated. The message may be cited.