TITLE: GCN CIRCULAR NUMBER: 30466 SUBJECT: Fermi trigger No 647942198: MASTER optical afterglow detection DATE: 21/07/18 08:52:30 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, T. Pogrosheva, V.Kornilov, E. Gorbovskoy, N.Tyurina, P.Balanutsa,V.Vladimirov, A.Kuznetsov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik,V.Topolev, F.Balakin, D.Cheryasov (Lomonosov Moscow State University,SAI, PhysicsDepartment), O.A. Gres, N.M. Budnev (Irkutsk State University, API), R. Podesta, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB210714.33 (trigger No 647942198) errorbox 150 sec after notice time and 181 sec after trigger time at 2021-07-14 07:59:34 UT, with upper limit up to 19.5 mag (Lipunov et al., GCN CIRCULAR 30461). MASTER-OAFA auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L ) discovered fast fading OT source at (RA, Dec) = 20h 53m 57.98s -53d 08m 20.3s on 2021-07-14.35751 UT. The OT unfiltered magnitude is 16.1m (mlim1 = 8.7). The OT is seen in 6 images. There is no minor planet at this place. We have reference image on 2016-07-30.14890 UT with 'BLANK' filter 20.3m. Follow up observations are required.