TITLE: GCN CIRCULAR NUMBER: 10354 SUBJECT: GRB 100122A: MASTER-Net optical observations DATE: 10/01/22 16:50:16 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs S.Sergienko, V.Yurkov 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 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 100122A (Fermi-GBM alert, TRIGGER_NUM: 285864459) 30 sec after first Notice time and 59 s after the GRB time . We have a number images with exposition from 5s to 180 s. The image limit from telescope ~17m . The image limit from Very Wide Filed Camera ~11.5. Fermi GBM error box locate in vicinity Orion Nebula. More accurate error-box is required. The image reduction is continued. The one of the first nice images MASTER VWF camera (with Orion constalation and trees) is available at http://observ.pereplet.ru/images/GRB100122A/grb.html . The message may be cited. mailto: lipunov@sai.msu.ru