TITLE: GCN CIRCULAR NUMBER: 16154 SUBJECT: GRB 140423A: Nanshan optical upper limit DATE: 14/04/23 17:26:52 GMT FROM: Dong Xu at DARK/NBI D. Xu (DARK/NBI), X. Zhang, C.-H. Bai, A. Esamdin, L. Ma (XAO) report: We observed the optical afterglow field of GRB 140423A (Sonbas et al., GCN 16142; Elenin et al., GCN 16143; Kaur et al., GCN 16144;) using the 1m telescope located at Nanshan, Xinjiang, China. Three R-band frames were obtained under rather bad weather. The afterglow has decayed down to a limiting magnitude of m(R)>19.4 mag at a mean time of 8.216 hr post-burst, calibrated with nearby SDSS stars.