{
  "bibcode": "2021GCN.30476....1Z",
  "body": "Z.P. Zhu (NAOC, HUST), S.Y. Fu, D. Xu, X. Liu (NAOC), X. Gao (Urumqi \nNo.1 Senior High School), J.Z. Liu (XAO) report:\n\nWe observed the field of GRB 210722A (D'Avanzo et al., GCN 30475) using \nthe NEXT-0.6m telescope located at Nanshan, Xinjiang, China. We obtained \na series of 40 s, 60 s, 90 s frames in the Sloan r-band, starting at \n20:56:45 UT on 2021-07-22, i.e., 123 s after the BAT trigger, among \nwhich part of the frames are useless due to the cloudy weather.\n\nAn uncatalogued optical transient is detected at the Swift/UVOT position \n(D'Avanzo et al., GCN 30475) with varying brightness, and thus confirms \nit as the optical afterglow of the burst. Preliminary analysis of the \nbeginning photometry is as follows:\n\nTmid-T0(sec)  Mag    MagErr\n143               14.33    0.01\n361               13.94    0.01\n452               14.01    0.01\n\nAll magnitudes are calibrated with the nearby PS1 field.",
  "circularId": 30476,
  "createdOn": 1626991102000,
  "email": "dxu@nao.cas.cn",
  "subject": "GRB 210722A: Nanshan/NEXT optical afterglow observations",
  "submitter": "Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>",
  "eventId": "GRB 210722A"
}