TITLE: GCN CIRCULAR NUMBER: 16999 SUBJECT: GRB 141031B: MASTER early optical observations DATE: 14/10/31 15:23:47 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University E. Gorbovskoy, V. Lipunov, M.Pruzhinskaya, V.Kornilov, D.Kuvshinov, N.Tyurina, N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, V.V.Chazov, D.Denisenko, A.Sankovich Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinsky, I.Zalozhnih, A. Popov Ural Federal University, Yekaterinburg, Kourovka 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) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Tunka was pointed to the GRB141031B 33 sec after notice time and 88 sec after trigger time at 2014-10-31 14:58:13 UT in two polarizations. On our first (20s exposure) set we haven`t found optical transient within SWIFT error-box (Gompertz et al GCN 16998). The 5-sigma upper limit has been about 16.0 mag MASTER II robotic telescope located in Kislovodsk was pointed to the GRB141031B 23 sec after notice time and 77 sec after trigger time at 2014-10-31 14:58:03 UT in two polarizations. On our first (20s exposure) set we haven`t found optical transient within SWIFT error-box. The 5-sigma upper limit has been about 15.5 mag. The message may be cited.