TITLE: GCN CIRCULAR NUMBER: 17237 SUBJECT: GRB 141225A: MASTER-SAAO first OT detection DATE: 14/12/26 10:41:39 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs D.Buckley, S. Potter, A. Kniazev, M. Kotze South African Astronomical Observatory E. Gorbovskoy,V. Lipunov, N.Tyurina P.Balanutsa, D.Denisenko, M.Pruzhinskaya,A.Kuznetsov, V.Kornilov, D.Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute O.Gres, K.Ivanov, S.Yazev, N.M.Budnev, V.A.Poleshchuk Irkutsk State University V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinsky, I.Zalozhnih, A. Popov Ural Federal University, Kourovka H. Levato and C. Saffe Instituto de Ciencias Astronomicas de la Tierra y del Espacio (ICATE), San Juan, Argentina C. Mallamacci, C. Lopez and F. Podest Observatorio Astronomico Felix Aguilar (OAFA), San Juan National University, Argentina MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru) installed several days ago in South African Astronomical Observatory (Sutherland) was automatically pointed to the Swift and Fermi GRB 141225A (Avanzo et. al. GCN 17229). Firstly MASTER-SAAO pointed by FERMI coordinates and made first exposure 28 sec. after FERMI trigger at 2014-12-25 23:02:28 UT. Then MASTER-SAAO pointed to the Swift coordinates 20 sec after Swift notice time and 113 sec after trigger time at 2014-12-25 23:03:00 UT in two polarizations. MASTER-SAAO discovered OT source (Gorosabel et. al. 17230, Malesani et. al 17232, Kuin et. al 17233, Xu et. al 17236): Ra: 09:15:06.94 Dec: +33:47:30.87 Mag: 17.5 The source is visible on the subsequent frames. The data reduction is continued. Our band is well described by a parity 0.8R+0.2B (USNO B1). This message may be cited.