TITLE: GCN CIRCULAR NUMBER: 18823 SUBJECT: GRB 160104A: Xinglong TNT optical observation DATE: 16/01/04 16:27:58 GMT FROM: L.P. Xin at NAOC L. P. Xin, X. F. Wang, J. Y. Wei, Y. L. Qiu, J. S. Deng, J. Wang, X. H. Han, C. Wu, D. Xu on behalf of EAFON report: We observed GRB 160104A (Melandri et al. GCN 18815) with Xinglong 0.8-m TNT telescope at 11: 26:01UT, 111 sec after the burst. The optical afterglow (Guidorzi et al., GCN 18816; Saito GCN 18817; Yurkov et al., GCN 18820 ) was detected in our white images. The brightness of the optical afterglow is about 18.45 mag at the mid time of 121 sec afer the burst, calibrated by the USNO B1.0 star (RA=05:07:08 DEC=11:02:02 R2=16.25mag). The message may be cited.