TITLE:   GCN CIRCULAR
NUMBER:  30684
SUBJECT: GRB 210822A: Nanshan/NEXT optical observations
DATE:    21/08/22 18:35:26 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

S.Y. Fu (NAOC), Z.P. Zhu (NAOC,HUST), X. Liu, D. Xu (NAOC), X. Gao 
(Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:

We observed the field of GRB 210822A (Page et al., GCN 30677) using the 
NEXT-0.6m telescope located at Nanshan, Xinjiang, China. We obtained 
15x100 s frames in the Sloan r-band and 10x100 s frames in the V-band, 
starting at 14:42:53 UT on 2021-08-22, i.e., 5.41 hr after the BAT trigger.

The optical afterglow (e.g., Page et al., GCN 30677; Zheng & Filippenko, 
GCN 30679) of the burst is clearly detected in our stacked images. 
Preliminary photometry results are as follows:

    Tmid (UT)            Tmid-T0(day)  Mag   MagErr  Filter
2021-08-22T14:58:04    0.236      18.53    0.06      r
2021-08-22T15:54:29    0.275      18.88    0.08      V

calibrated with nearby PanSTARRS stars.