TITLE: GCN CIRCULAR NUMBER: 10798 SUBJECT: GRB 100526A: MASTER-Net optical alert observations DATE: 10/05/26 19:02:59 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.Yurkov, Yu.Sergienko, D.Varda, A.Garusina 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.Zalozhnich, 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 ponted to the GRB 100526A (L. Vetere et al. gcn 10797) 21 min after burst. For the unknown reason any of our observatories hasn't received socket alert on this burst (we have received only auxiliary packages). We have a number images with 60-s exposition. We haven't found optical transient within Swift-XRT error-box. The 3-sigma unfiltred upper limit has been about 17.0 mag on single and 18.2 mag on 10 images coadd. http://observ.pereplet.ru/images/GRB100526A/grb100526.jpeg The message may be cited. mailto: lipunov@sai.msu.ru