{
  "bibcode": "2017GCN.21795....1F",
  "body": "H.X. Feng, D. Xu, Z.P. Zhu (NAOC), S.G. Ma, T.Z. Yang, J.H. Liu, P. \nZong, H.B. Niu, J.Z. Liu,  A. Esamdin, L. Ma (all XAO), Y.D. Hu \n(IAA-CSIC), Y. Qing (Geneva Observatory) report:\n\nWe observed the field of GRB 170903A (Markwardt et al., GCN 21793) using \nthe 1m telescope located at Nanshan, Xinjiang, China. We obtained 3x180s \nR-band frames, starting at 14:08:09 UT on 2017-09-03, i.e., 1.317 hr \nafter the burst.\n\nNo optical source is detected at the XRT position (Campana et al., GCN \n21794) in the stacked image, down to a limiting magnitude of m(R)~21.3, \ncalibrated with the nearby SDSS field.",
  "circularId": 21795,
  "createdOn": 1504450909000,
  "email": "dxu@nao.cas.cn",
  "subject": "GRB 170903A: Nanshan optical upper limit",
  "submitter": "Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>",
  "eventId": "GRB 170903A"
}