TITLE: GCN CIRCULAR NUMBER: 7410 SUBJECT: GRB080310: Optical observation by MITSuME telescope DATE: 08/03/11 15:55:27 GMT FROM: Michitoshi Yoshida at Okayama Astrophysical Obs M. Yoshida, K. Yanagisawa, Y. Shimizu, S. Nagayama, H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We detected the optical afterglow of GRB 080310 (Cummings, et al., GCN 7382) in the error circle of the XRT position (Osborne et al. GCN 7394) with the 50cm MITSuME Telescope at Okayama Astrophysical Observatory on March 10 UT. Photometric calibration was done using USNO-B1.0 catalog. The light curve shows a plateau at around 19:00 - 20:00 UT (about 11 hours after the trigger). The photometric results are summarized below. Observation date: 2008-03-10 UT mid-UT exp-T g' Rc Ic ------------------------------------------------------------ 15:09:46 60min 20.0+-0.2 19.7+-0.3 19.1+-0.2 16:24:47 60min 20.4+-0.2 20.2+-0.2 19.5+-0.2 17:39:46 60min 20.6+-0.1 20.4+-0.2 19.8+-0.2 18:54:44 60min 20.6+-0.2 20.5+-0.1 20.2+-0.3 19:57:05 42min 20.6+-0.2 20.3+-0.1 20.0+-0.2 ------------------------------------------------------------