TITLE: GCN CIRCULAR NUMBER: 10393 SUBJECT: GRB 100131A: MASTER-Net optical alert observations DATE: 10/02/07 13:47:58 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.Yurkov, S.Sergienko Blagoveschensk Educational State University, Blagoveschensk E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina, D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov, D.Zemnukhov, M. Kornilov Sternberg Astronomical Institute, Moscow State University A. Tlatov, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinski, I.Zalozhnih, T.Kopytova, A. Popov Ural State University, Kourovka K.Ivanov, S.Yazev, N.M.Budnev, E.Konstantinov, V.Lenok Irkutsk State University MASTER robotic telescope (MASTER-Net: http://observ.pereplet.ru, 200 mm, FOV=8 square degrees (testing mode)) and Very Wide Field Camera (D=50 mm, 1000 square degrees, 11 Mpx, 36" per pix, mounted on telescope) located at Blagoveschensk was responted to the GRB 100131A (Fermi GBM alert, Goldstein et al, GCN CIRC 10358) 76 sec after first Notice time and 93 s after the GRB time. The center FOV of the main telescope correspond to first alert imformation: RA=107.420+-3 DEC=+3.730+-3 The limit of the main telescope images is aboute 15 mag (unfiltered). We have a number images with 5 s exposition from Very Wide Field Camera. The image limit from Very Wide Filed Camera ~10 mag. There is now OT in our images inside Fermi error box (A. Goldstein, GCN CIRC 10358) brighter 10 mag. The imege is available at http://observ.pereplet.ru/images/GRB100131A/grb100131A.jpg . The circles correspond to 1sigma + systematic Fermi error box, and 3sigma+systematic error box. The message may be cited. mailto: lipunov@sai.msu.ru