TITLE: GCN CIRCULAR NUMBER: 21652 SUBJECT: GRB 170822A: MITSuME Akeno Optical Observation DATE: 17/08/23 07:15:59 GMT FROM: Katsuhiro L. Murata at Nagoya U K. L. Murata, Y. Saito, R. Itoh, Y. Tachibana, T. Yoshii, S. Harita, K. Morita, T. Ozawa, H. Mamiya, K. Shiraishi, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We searched for the optical counterpart of GRB 170822A (Melandri et al., GCN Circular #21640) 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 2017-08-22 16:27:38.15 UT . We did not find any new point source within enhanced XRT circle (Evans et al., GCN Circular #21643) in all three bands. We obtained following limits for the magnitudes. T0+[hour] MID-UT T-EXP[sec] g' Rc Ic ------------------------------------------------------------------------------------------------------- ~7.21 16:48:33.09 2280 >20.8 >20.1 >18.9 ------------------------------------------------------------------------------------------------------- T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used GSC2.3 catalog for flux calibration.