TITLE: GCN CIRCULAR NUMBER: 16972 SUBJECT: GRB 141028A: MASTER OT candidate detection DATE: 14/10/28 19:35:30 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs E. Gorbovskoy, V. Lipunov, N.Tyurina, M.Pruzhinskaya, V.Kornilov, D.Kuvshinov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D.Denisenko Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A. Gabovich Blagoveschensk Educational State University, Blagoveschensk 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 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 Kislovodsk was pointed to the GRB141028A (GCN 16969, Bissaldi) in survey mode. MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 21h 30m 24.51s -00d 13m 52.3s on 2014-10-28.76451 UT. The OT unfiltered magnitude is 18.9m (limit 19.9m). The OT is seen in 12 images. There is no minor planet at this place. We have reference image without OT on 2014-07-22.97505 UT with unfiltered magnitude limit 19.7m. Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/213024.51-001352.3.png This message may be cited.