TITLE:   GCN CIRCULAR
NUMBER:  23588
SUBJECT: GRB 181228A: Xinglong-2.16m optical upper limit
DATE:    18/12/29 13:31:29 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

Z.P. Zhu, L.P. Xin, D. Xu, J.B. Zhang (NAOC), X. Zhang, J.H. Liu (XAO) 
report:

We observed the field of GRB 181228A (Moss et al., GCN 23570) using the 
2.16-m telescope located at Xinglong, Hebei, China, equipped with the 
BFOSC camera. We obtained 6x300s and 2x600s frames in I-band, starting 
at 13:04:00 UT on 2018-12-28, i.e., 10.18 hrs after the BAT trigger.

The afterglow of GRB 181228A  (e.g., Moss et al., GCN 23570; D'Avanzo et 
al., GCN 23575; Lipunov et al., GCN 23576) is not detected in our 
stacked image, down to a limiting magnitude of ~20.5 mag, calibrated 
with the nearby PanSTARRS field.