TITLE: GCN CIRCULAR NUMBER: 19212 SUBJECT: GRB 160321A: MASTER observations zero Galaxy latitude GRB DATE: 16/03/21 17:01:43 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.V.Chazov Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Senik Kislovodsk Solar Station of the Pulkovo Observatory K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Kislovodsk was pointed to the GRB160321A 6 sec after notice time and 68 sec after trigger time at 2016-03-21 15:56:35 UT. We do not found optical transient within SWIFT error-box (Stamatikos et al., GCN 60321A) brighter then 13.1. After Sunset we found: Pro.type Date time Exp.time Limit Filt. Tube. Alert 2016-03-21 16:43:44 180 18.6 W WEST Alert 2016-03-21 16:43:44 180 18.1 W EAST Alert 2016-03-21 16:40:18 180 18.6 W WEST Alert 2016-03-21 16:36:45 180 18.6 W WEST Alert 2016-03-21 16:36:45 180 18.1 W EAST Alert 2016-03-21 16:33:16 180 18.5 W WEST Alert 2016-03-21 16:28:25 180 17.6 P WEST Alert 2016-03-21 16:28:25 180 17.6 P EAST Alert 2016-03-21 16:21:39 180 17.4 P EAST The galaxy latitude is about zero. So this is the optical free GRB. The message may be cited.