TITLE: GCN CIRCULAR NUMBER: 23490 SUBJECT: GRB 181202A: Global MASTER-Net optical observations DATE: 18/12/03 01:24:30 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory K. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk Irkutsk State University V. Yurkov, A. Gabovich, Yu. Sergienko Blagoveschensk Educational State University, Blagoveschensk R. Podesta, Carlos Lopez and F. Podesta Observatorio Astronomico Felix Aguilar (OAFA) Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias D. Buckley, S. Potter, A. Kniazev, M. Kotze South African Astronomical Observatory MASTER-Tunka robotic telescope (MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the Swift GRB 181202A (Cannizzo et al., GCN #23482) 13216 sec after trigger time at 2018-12-02 10:17:08. On best sum (1800s total exposure) set we haven`t found optical transient within Swift error-box (ra=280.733 dec=27.9592 r=0.05). The 5-sigma upper limit has been about 19.0 mag ==================================================================== The galactic latitude b = 14 deg., longitude l = 58 deg. The observations made on zenit distance = 42 deg.The moon (25 % bright part) below the horizon (The altitude of the Moon is -26 deg. ). Observations started at twilight. The sun altitude is -10.6 deg. The object can be observed till sunrise at 2018-12-02 00:56:06 MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the SWIFT GRB181202.28 32902 sec after trigger time at 2018-12-02 15:46:09 UT, with upper limit up to 20.2 mag. No OT detected. The observations began at zenit distance = 57 deg. The sun altitude is -23.0 deg. This message can be cited.