TITLE: GCN CIRCULAR NUMBER: 22661 SUBJECT: GRB 180418A: Xinglong TNT optical upper limit DATE: 18/04/19 02:51:03 GMT FROM: L.P. Xin at NAOC L. P. Xin, J. Z. Yan, J. Y. Wei, Y. L. Qiu, J. S. Deng, J. Wang, X. H. Han, X. M. Meng, C. Wu, D. TURPIN, H. L. Li report: We began to observe GRB 180418A (D'Elia et al., GCN 22646) with Xinglong 0.8-m TNT telescope, China, at 2018-04-18, 14:23:11(UT), about 7.8 hours after the burst. We obtained 10 R-band images with an exposure time of 300 sec for each frame. The optical afterglow (Zheng & Filippenko, GCN 22647; Guidorzi et al., GCN 22648; Troja et al., GCN 22652; Fong et al., GCN 22659; Malesani et al., GCN 22660 ) was not detected in our stacked image with 10*300 sec. The 3 sigma upper limit is estimated to be about R~20 mag calibrated by USNO B1.0 R2 mag at about 8.2 hours after the burst, We acknowledge the excellent support from Xinglong staff YunPeng Wang.