TITLE: GCN CIRCULAR NUMBER: 19344 SUBJECT: GRB 160425A : MASTER earlier optical observations DATE: 16/04/26 00:25:58 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, P.Balanutsa, A.Kuznetsov, D.Kuvshinov Lomonosov Moscow State University, Sternberg Astronomical Institute D.Buckley, S. Potter, A.Kniazev South African Astronomical Observatory K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in SAAO was pointed to the GRB 160425A (trigger time 23:26:11.34) at 2016-04-25 23:28:59UT. On our first (30s, t_start=2016-04-25 23:28:59UT, m_lim=17.3, polarization) exposition there is marginally seen optical transient within SWIFT error-box up (H. A. Krimm et al., GCN #19343) at RA=280.32738,-54.36004 The observations will be continued.