TITLE: GCN CIRCULAR NUMBER: 17978 SUBJECT: GRB 150627A: MASTER-SAAO OT Detection DATE: 15/06/28 09:35:42 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, P.Balanutsa,A.Kuznetsov,D.Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory Rafael Rebolo, Miquel 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) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in SAAO was pointed to the GRB150627.18 10133 sec after notice time and 55479 sec after trigger time at 2015-06-27 19:48:02 16:32:07 UT. On our first (180s exposure) set we found optical transient within LAT error-box (ra=07 49 57 dec=-51 33 34 r=0.500000, Arimoto et al., GCN 17791) brighter then 16.87. 07h 49m 53.05s , -51d 29m 21s.4 error =+-1.0 m ~ 19.0 This postion 2 arcsec close X-ray position (Gompertz et al., 17976) The 5-sigma upper limit has been about 16.87mag The message may be cited.