TITLE: GCN CIRCULAR NUMBER: 22238 SUBJECT: GRB 171210A: MASTER-Net optical observations DATE: 17/12/11 14:56:17 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs N.Tyurina, V. Lipunov, E. Gorbovskoy,V.Kornilov, D.Kuvshinov, A.V.Krylov, I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA), National University of San Juan, Argentina H. Levato, C. Saffe Instituto de Ciencias Astronomicas,de la Tierra y del Espacio (ICATE), San Juan, Argentina D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias O.Gres, K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk, Irkutsk State University V.Yurkov, Yu.Sergienko Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory MASTER-IAC robotic telescope (http://observ.pereplet.ru) started Fermi LAT GRB171210A (Bissaldi et al. GCN 22228, t_trigger=2017-12-10 11:49:15.26UT, RA, Dec = 335.29, 24.44 (J2000), 0.15deg (90%) stat.err.rad.) inspection at 2017-12-10 19:08:16UT (07h19m00.7s after trigger time) just after sunset. The unfiltered mlim on the single images is 20.4 (180s exposition), and on the sum is 21m. MASTER auto-detection System (Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) didn't find optical counterpart. http://observ.pereplet.ru/images/MASTERGRB171210AFermi.jpg Observations were made on zenit distance = 14 degrees, galaxy latitude b = -27 degree. Dist. to Moon: 144.183815 Moon coord.: (176.084576 d, 5.105187 d Lunar disk: 0.451595 Lunar phase: 95.555548 The sun altitude is -12.79 This message can be cited.