TITLE: GCN CIRCULAR NUMBER: 22274 SUBJECT: GRB 171222A: Nanshan-1m optical afterglow detection DATE: 17/12/23 14:00:59 GMT FROM: Dong Xu at NAOC/CAS X. Zhang, P. Zong, J.H. Liu (XAO), H.X. Feng, Z.P. Zhu, D. Xu (NAOC), H.B. Niu, J.Z. Liu, A. Esamdin, L. Ma, Y. Zhang (XAO) report on behalf of a larger collaboration: We observed the field of GRB 171222A (Racusin et al., GCN 22265) using the 1m telescope located at Nanshan, Xinjiang, China. We obtained 6x300s R-band frames, starting at 18:14:36 UT on 2017-12-22, i.e., 1.83 hr after the BAT trigger. An uncatalogued and fading optical transient (OT) is detected at the XRT position (Osborne et al., GCN 22266) as well as the NOT position (Perley et al., GCN 22269) in our images. Preliminary photometry results are as follows: Tmid-T0 Exposure Filter Mag(R) MagErr(R) (hr) (s) 1.87 1x300 R 20.86 0.21 2.68 3x300 R 21.47 0.22 7.87 2x300 R 21.72 0.22 Photometry is calibrated with nearby USNO-B1.0 stars (R2 magnitudes), and errors are only statistical values. We thus conclude that this OT is the optical afterglow of GRB 171222A.