GCN Circular 14628
M. Im (CEOU/SNU), H.-I. Sung (KASI), & Y. Urata (NCU) on behalf of a larger collaboration We observed GRB 130511A (Krimm et al., GCN 14620) in BVRI filters using a 0.6m telescope at the Sobaeksan Optical Astronomy Observatory (SOAO), starting at 76min after the BAT alert. In stacked images of 6 x 300sec exposures, we identify the optical afterglow with the following magnitude (Cucchiara et al. GCN 14621; Takaki et al. GCN 14626), calibrated against a USNO-B1 star in the vicinity. T(mid, UT) Mag 05-11 13:50:12 R=20.78 +- 0.13 The afterglow is detected in the other bands, but at a lower S/N. We thank the staffs at SOAO for performing the observation.