TITLE: GCN CIRCULAR NUMBER: 18276 SUBJECT: GRB 150910A: MITSuME Ishigakijima Optical Observation DATE: 15/09/11 04:46:31 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ), K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME and OISTER collaboration: We observed the field of GRB 150910A (Pagani et al., GCNC 18264) with the optical three color (g', Rc and Ic) CCD camera attached to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory. The observation started on 2015-09-10 12:21:44 UT (~3.3 h after the burst). We detected the previously reported afterglow (Pagani et al., GCNC 18264; Zheng and Filippenko, GCNC 18265; Dichiara et al., GCNC 18266; Kuroda et al., GCNC 18267) in all the three bands. Photometric results of the OT are listed below. We used GSC2.3 catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' g'_err Rc Rc_err Ic Ic_err ----------------------------------------------------------------------- 0.14010 12:26:33 540.0 19.1 0.1 18.8 0.1 18.4 0.1 ----------------------------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec]