TITLE: GCN CIRCULAR NUMBER: 19466 SUBJECT: GRB 160525B: Nanshan optical upper limit DATE: 16/05/25 21:32:53 GMT FROM: Dong Xu at NAOC/CAS D. Xu, Y.-H. Han (both NAOC/CAS), S.-G. Ma, A. Esamdin, J.-Z. Liu, L. Ma (all XAO) report: We observed the field of GRB 160525B (Krimm et al., GCN 19459) using the 1m telescope located at Nanshan, Xinjiang, China. We obtained 5x300s R-band frames, starting at 15:26:24 UT on 2016-05-25, i.e., 6.02 hr after the burst. No optical source is detected at the XRT position (Beardmore et al., GCN 19463) in the stacked image, down to a limiting magnitude of m(R)>21.5, calibrated with the nearby SDSS field.