TITLE: GCN CIRCULAR NUMBER: 14466 SUBJECT: GRB 130427A: GMG optical observation DATE: 13/04/27 17:32:43 GMT FROM: Xiao-hong Zhao at Yunnan Obs X.-H. Zhao (YNAO and PSU), J. Mao (RIKEN and YNAO), Y. X. Xin(YNAO), J.-M. Bai (YNAO) report on behalf of a larger collaboration: We observed the field of GRB 130427A (Maselli et al., GCN 14448) with 2.4m Gao-Mei-Gu (GMG) telescope. Observation was started at 13:25:18 UT on 2013-04-27 (i.e., 5.6 hrs after the burst) under a bad weather condition. The sloan filters of g', r',i' and z' were used. The afterglow is very bright in every band with magnitudes of g'~16.36, r'~16.1, i'~15.9 and z'~15.8. The observations are ongoing. We thank the GMG staff, especially Hong-Yan Gao and Jian-Duo He for performing these observations.