TITLE: GCN CIRCULAR NUMBER: 12767 SUBJECT: GRB 111228A: GMG optical observation DATE: 11/12/29 15:16:14 GMT FROM: Xiao-hong Zhao at Yunnan Observatory X.-H. Zhao (YNAO), D. Xu (WIS/NAOC), J.-R. Mao (KASI/YNAO), J.-M. Bai (YNAO) report: We observed the field of GRB 111228A (Ukwatta et al., GCN 12737) at the 2.4m Gao-Mei-Gu (GMG) telescope equipped with YFOSC. Observations started at 16:31:38 UT on 2011-12-28 (i.e., 47 mins after the burst) and 4x600s R-band images were obtained in a seeing of ~3.36". We found the afterglow was decaying. The results are as follows: mid time (UT) magnitude (err) 2011-12-28 16:36:38 17.11 (0.01) 2011-12-28 17:19:14 17.42 (0.01) 2011-12-28 17:44:57 17.56 (0.01) 2011-12-28 17:56:15 17.62 (0.01). The magnitudes were calibrated with the USNO-B1 #1083-0199833 star (R2 = 17.28 mag; also used by Klotz et al., GCN 12746; Nascimbeni et al., GCN 12748; Xu et al., GCN 12750; Hentunen et al., GCN 12754). Further observations are planned. We thank the GMG staff, especially Y.-X. Xin, Fen He, and Gui-Hua He for performing these observations. [GCN OPS NOTE(29dec11): Per author's request, the affiliation of X-H.Z. was changed to Yunnan Observatory.]