TITLE: GCN CIRCULAR NUMBER: 18234 SUBJECT: GRB 150902A: MASTER-SAAO optical observations DATE: 15/09/03 16:56:26 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory E. Gorbovskoy, V. Lipunov, N.Tyurina, V.Kornilov, P.Balanutsa, A.Kuznetsov, E.Popova, D.Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory K.Ivanov, O.Gres, N.M.Budnev, S.Yazev, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A.Gabovich Blagoveschensk Educational State University, Blagoveschensk V.Krushinski, I.Zalozhnih Ural Federal University, Kourovka Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Carlos Lopez, Claudio Mallamaci and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in SAAO was firstly pointed to the GRB150902A (Roberts et. al. GCN 18229) 67 sec after trigger time at 2015-09-02 17:36:47 UT. On our first (10s exposure) set we not found optical transient within FERMI error-box (ra=16 24 36 dec=-72 54 35 r=2.140000) brighter then 15.27. MASTER-SAAO robotic telescope makes several alert and inspect observations inside actual (at that time) FERMI GBM error boxes, but all of that frames located far away from the final FERMI LAT (Arimoto et. al GCN 18228) error box and did not cover it. MASTER-VWF very wide fileld cameras placed in MASTER-SAAO cover FERMI LAT error box at 2015-09-02 17:36:32.0 i.e. 47 sec after notice and 53 sec after trigger time, and imaging it continuously without time gaps till 2015-09-02 17:43:00. We have not find OT inside FERMI LAT error box with upper limit 11.5m on single (5 second) and 12.8m ( on coadd of 12 frames with total exposure 60 s) images. The message may be cited.