TITLE: GCN CIRCULAR NUMBER: 23333 SUBJECT: GRB 181013A: Global MASTER Net optical observations DATE: 18/10/13 06:51:18 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-Kislovodsk robotic telescope (MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the GRB181013A (D'Avanzo et al., GCN 23332) 21 sec after notice time and 54 sec after trigger time at 2018-10-13 02:40:23 UT . On our first (10s exposure) set we haven`t found optical transient within SWIFT error-box (ra=207.596 dec=40.1783 r=0.05). The 5-sigma upper limit has been about 13.2 mag The message may be cited. ==================================================================== The galactic latitude b = 72 deg., longitude l = 82 deg. The observations made on zenit distance = 71 deg.The moon (18 % bright part) below the horizon (The altitude of the Moon is -50 deg. ). Observations started at twilight. The sun altitude is -7.8 deg. The object can be observed till sunrise at 2018-10-13 03:20:48. MASTER-Tavrida robotic telescope (MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the GRB181013.11 129 sec after notice time and 202 sec after trigger time at 2018-10-13 02:42:51 UT. On our first (40s exposure) set we haven`t found optical transient within SWIFT error-box (ra=207.596 dec=40.1781 r=0.1). The 5-sigma upper limit has been about 17.4 mag The message may be cited. ==================================================================== The galactic latitude b = 72 deg., longitude l = 82 deg. The observations made on zenit distance = 75 deg.The moon (18 % bright part) below the horizon (The altitude of the Moon is -54 deg. ). Observations started at twilight. The sun altitude is -13.6 deg. The object can be observed till sunrise at 2018-10-13 03:56:18. This message can be cited.