TITLE: GCN CIRCULAR NUMBER: 11981 SUBJECT: GRB 110426A: MASTER synchronous with MAXI/GSC observations DATE: 11/04/28 08:09:19 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs O. Gres, K.Ivanov, V.A.Poleshchuk, S.Yazev, N.M.Budnev, O.Chuvalaev Irkutsk State University E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov, D.Zimnukhov, M. Kornilov, A.Kuznetsov, D.Zimnukhov, M. Kornilov, A.Sankovich Sternberg Astronomical Institute, Moscow State University A. Tlatov, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinski, I.Zalozhnich, T.Kopytova, A. Popov Ural State University, Kourovka V.Yurkov, Yu.Sergienko, D.Varda, I.Kudelina Blagoveschensk Educational State University, Blagoveschensk First we pointed to FERMI trigger N325523188 (ra=217.133 dec=-12.333 err=32.42) at 15:07:28 (62 sec after trigger time). We observed this area to 15:08:33, until the next more exact FERMI alert (ra=205.160 dec=-11.570 err=10.9) comes. Unfortunately, after that replacement, the part of MAXI error-box has left a FOV of ours widefield cameras. We observ this new place to 15:13:33. We coadd all wide field (500 square degrees) camera unfiltered images. There is no OT from automatical identification. So we have following results: T_start T_s-T_fermi T_s-T_maxi exptime limit Cover_MAXI 15:07:28 62 sec -68 sec 55 sec 13.0 100 % 15:08:33 126 sec -3 sec 250 sec 13.8 85 % First epoch image http://observ.pereplet.ru/images/evgeny/grb110426a1.jpeg Second epoch image http://observ.pereplet.ru/images/evgeny/grb110426a2.jpeg Black lines is MAXI error_box. The main MASTER telescopes (40 sm) also made observations in 2 polarizations, in the center of each of FERMI error-boxes, but them FOV (4 sq. degree) it has appeared not enough for observ at least parts MAXI error-box.