TITLE:   GCN CIRCULAR
NUMBER:  23788
SUBJECT: GRB 190123A: NEXT-0.6m optical limit
DATE:    19/01/24 17:11:59 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

D. Xu, Z.P. Zhu (NAOC) report on behalf of a larger collaboration

We observed the field of GRB 190123A (D'Ai et al., GCN Circ. 23769) with 
the robotic NEXT-0.6m telescope located at Nanshan, Xinjiang, China. We 
obtained 3x40s, 4x60s, 3x90s R-band frames, starting at 12:20:56 UT on 
2019-01-23, i.e., 103 sec after the BAT trigger.

No optical afterglow consistent with the XRT position (Beardmore et al. 
GCN Circ. 23771) is detected in the stacked image, download a limiting 
magnitude of R~19.5, calibrated with the USNO-B1 catalog.