GCN Circular 29201

L. P. Xin(NAOC),  X. H. Han(NAOC), J. Y. Wei(NAOC),  L. H. Li(NAOC), 
J. Wang(GXU), D. Turpin(CEA),  H. B. Cai(NAOC), X. Y. Wang(NJU),   
C. Wu(NAOC),  X. G. Wang(GXU),  Z. G. Dai (NJU), G. W. Li(NAOC),  
E. W. Liang (GXU),  S.S.Sun(GXU), L. Huang(NAOC), X. M. Lu(NAOC),  
Y. G. Yang(HNU), C. Gao(GXU), Y. L. Qiu(NAOC), and J. S. Deng(NAOC) report: 


The optical counterpart of GRB 201223A (Gropp et al., GCN #29158, 
Wood et al., GCN #29161) reported by (Lipunov et al., GCN #29157; 
Gropp et al., GCN #29158; Zhu et al., GCN #29159; Hu et al., GCN #29160;
Hosokawa et al., GCN #29164; Filipp Dmitrievich Romanov GCN #29165;
Xin et al., GCN #29166; Belkin et al., GCN #29167;  Kumar et al., GCN #29168; 
Xu et al., GCN #29169; Gupta te al., GCN #29173; Pankov et al., GCN #29174;
Kumar et al., GCN #29176; Belles et al., GCN #29177 )
was detected  by Ground Wide Angle Camera (GWAC) in white band 
at Xinglong observatory, China, during the Swift prompt emission phase. 
The exposure time for each GWAC image is 10 seconds. 

Preliminary process showed that the brightness was about R~15.5 mag at ~2 sec after the burst, 
and then brighten to the peak of R~14.8 mag at about 80 sec  post the trigger time.

All these magnitudes were calibrated to USNO B1.0 R2 mag catalog. 

More analyses are still continuing.