TITLE: GCN CIRCULAR NUMBER: 20063 SUBJECT: GRB161017.74 MASTER-Net OT detection DATE: 16/10/17 17:55:48 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.V.Chazov, Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Senik Kislovodsk Solar Station of the Pulkovo Observatory D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Blagoveschensk was pointed to the GRB161017.74 70 sec after notice time and 96 sec after trigger time at 2016-10-17 17:53:27 UT. On our 3-th (20s exposure) set we found 1 optical transient within SWIFT error-box (ra=09 31 03 dec=+43 08 31 r=0.050000) brighter then 14.5. T-Tmid Date Time Expt. Ra Dec Mag ---------|---------------------|-------|-----------------|-----------------|------- 106 2016-10-17 17:53:27 20 ( 9h 31m 04.6s , +43d 7m 35.9s) 13.44 The 5-sigma upper limit has been about 14.5mag The message may be cited.