{
  "bibcode": "2021GCN.29623....1Z",
  "body": "Z.P. Zhu (NAOC, HUST), S.Y. Fu, X. Liu, D. Xu (NAOC), X. Gao (Urumqi \nNo.1 Senior High School), J.Z. Liu (XAO) report:\n\nWe observed the field of GRB 210308A (D'Elia et al., GCN 29619) using \nthe NEXT-0.6m optical telescope located at Nanshan, Xinjiang, China. \nObservations started at 14:16:29 UT on 2021-03-08, i.e., 7.67 hr after \nthe BAT trigger. We obtained 15x200 s frames in the Sloan r- and i- \nbands, respectively.\n\nThe optical afterglow (D'Elia et al., GCN 29619) of the burst is not \ndetected in our stacked images, down to limiting magnitudes of r ~ 21.7 \nand i ~ 21.3, calibrated with nearby PS1 stars.",
  "circularId": 29623,
  "createdOn": 1615220870000,
  "email": "dxu@nao.cas.cn",
  "subject": "GRB 210308A: Nanshan/NEXT optical upper limits",
  "submitter": "Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>",
  "eventId": "GRB 210308A"
}