TITLE: GCN CIRCULAR NUMBER: 18485 SUBJECT: GRB 151027A: Weihai optical observations DATE: 15/10/27 12:17:48 GMT FROM: Dong Xu at NAOC/CAS D. Xu (NAOC/CAS), C.-M. Zhang, C. Cao, S.-M. Hu (SDU) report: We observed the field of GRB 151027A (Maselli et al., GCN 18478) using the 1m telescope located at Weihai, Shandong, China. Observations started at 09:44 UT on 2015-07-27, i.e., 5.77 hr after the burst. We obtained 5x300s R-band and 5x150s I-band frames. The afterglow (e.g., Maselli et al., GCN 18478; Zheng & Filippenko, GCN 18479; Elenin et al., GCN 18480; Perley & Cenko, GCN 18481) is clearly detected in each image, and it has decayed to m(R) = 16.0 +/- 0.1 mag for the first R-band exposure, calibrated with the nearby USNO B1 stars (with R2 magnitudes).