TITLE: GCN CIRCULAR NUMBER: 19008 SUBJECT: GRB 160206A: Kiso/KWFC optical observations DATE: 16/02/10 04:46:44 GMT FROM: Tomoki Morokuma at U of Tokyo Tomoki Morokuma (The University of Tokyo), Nozomu Tominaga (Konan University), Masaomi Tanaka (National Astronomical Observatory of Japan), Akihiro Suzuki (Kyoto University), Motoko Serino (RIKEN), Takanori Sakamoto (Aoyama Gakuin University), and Keiichi Maeda (Kyoto University) report: We took r-band images for the field of GRB 160206A (Furuya et al. 2016, GCN Circ. 18993) 10.5 hours after the trigger with the Kiso Wide Field Camera (KWFC; Sako et al. 2012, SPIE, 8446, 84466L) on the 1.05-m Kiso Schmidt telescope in Japan. Our data were taken in a very low elevation (10-15 degrees) and the detection limits were 17.0 mag (S/N=5, without the Galactic extinction correction). No optical afterglow is detected at the position of Swift XRT source 2 (Page et al. 2016, GCN Circ. 18996) in any of our ten 180-sec exposures. The Swift XRT source 1 (TYC 7149-2271-1) is saturated in all the images and it is difficult to evaluate its time variability. Starting times (UT) of the exposures are summarized as below. date(UT) time t_exp[s] 2016-02-06 13:27:19 180 2016-02-06 13:32:51 180 2016-02-06 13:38:17 180 2016-02-06 13:43:43 180 2016-02-06 13:49:06 180 2016-02-06 13:54:36 180 2016-02-06 14:00:01 180 2016-02-06 14:05:26 180 2016-02-06 14:10:50 180 2016-02-06 14:16:17 180