TITLE: GCN CIRCULAR NUMBER: 22971 SUBJECT: GRB 180718B: MASTER optical observation DATE: 18/07/20 12:48:11 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs E. Gorbovskoy, V. Lipunov, V.Kornilov, N.Tiurina, A.Kuznetsov, V.Chazov, I. Gorbunov, D. Vlasenko, D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov Lomonosov Moscow State University,SAI D. Buckley, South African Astronomical Observatory (SAAO) R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias (IAC) A. Tlatov, V.Senik, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory R. Podesta, F. Podesta, C. Lopez, C.Francile Observatorio Astronomico Felix Aguilar (OAFA) H.Levato, Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) O. Gres, N.M.Budnev , Yu.Ishmuhametova Irkutsk State University (ISU) A. Gabovich, V. Yurkov, Yu. Sergienko Blagoveschensk Educational State University (BSPU) MASTER-OAFA robotic telescope (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) was pointed to the GRB180718.76 36087 sec after notice time and 36087 sec after trigger time at 2018-07-19 04:19:52 UT. On our combined images (1800 s), started 41401 sec after tigger time at 2018-07-19 05:48:25 UT, we not found optical transient within LAT error-box (ra=44.6792 dec=-31.5 r=1) brighter then 20.4. The observations made on zenit distance = 74 degrees, galaxy latitude b = -62 degree. The moon (44 % bright part) below the horizon (The altitude of the Moon is -20 degree ). The sun altitude is -71.7 degree. The object can be observed till sunrise at 2018-07-19 11:33:26 . The message may be cited.