TITLE: GCN CIRCULAR NUMBER: 16653 SUBJECT: GRB 140801A (FERMI trigger 428612396): MASTER brigth OT discovery DATE: 14/08/01 20:52:09 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs E. Gorbovskoy, V. Lipunov, D.Denisenko, M.Pruzhinskaya, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, V.V.Chazov, A.Sankovich 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.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 GRB140801A (FERMI trig. 428612396) 54 sec after notice time and 100 sec after trigger time at 2014-08-01 19:01:33 UT in two polarizations. MASTER-Tunka auto-detection system discovered bright OT source at (RA, Dec) = 02h 56m 16.44s +30d 56m 16.8s on 2014-08-01.79376 UT. The OT unfiltered magnitude is 14.6m (limit 18.3m) within FERMI error-box (trig. N 428612396). Preliminary automatic photometry and astrometry Date Time Ra Dec Mag 2014-08-01 19:01:31.886 02h 56m 16.42s , +30d 56m 16s.8 14.64 2014-08-01 19:03:02.863 02h 56m 16.43s , +30d 56m 17s.0 15.72 2014-08-01 19:04:38.384 02h 56m 16.43s , +30d 56m 17s.0 16.30 Our band is well described by a parity 0.8R+0.2B (USNO B1). The discovery and reference images are available at: http://master.sai.msu.ru/static/GRB/GRB140801_FERMI.png The 5-sigma upper limit has been about 18.53mag The message may be cited.