TITLE: GCN CIRCULAR NUMBER: 17920 SUBJECT: GRB 150608A: MITSuME Akeno optical upper limits DATE: 15/06/12 05:00:24 GMT FROM: Taketoshi Yoshii at Tokyo Tech Y.Saito, T.Fujiwara, T. Yoshii, Y. Tachibana, H. Ohuchi, Y. Yano, S. Kurita, Y.Ono, S.Harita, Y.Muraki, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 150608A (M.Arimoto et al., GCN Circular #17912) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. The observation started on 2015-06-09 18:17:37 UT (~30.5 h after the burst). We cound not detect any optical point source in the error circle of the previously reported afterglow detected by Swift-XRT (M.G.Bernardini et al., GCN Circular #17917) in all three bands. Three sigma upper limits are listed below. T0+[hour] MID-UT T-EXP[sec] g' Rc Ic --------------------------------------------------------------------------------------- 30.5131 18:23:03 600 > 17.9 > 18.0 > 17.4 --------------------------------------------------------------------------------------- T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used GSC2.3 catalog for flux calibration