{
  "bibcode": "2021GCN.29692....1P",
  "body": "N. Pankov (HSE), S. Nazarov (CrAO), A. Pozanenko (IKI),  S. Belkin (IKI) \nreport  on behalf of GRB IKI FuN:\n\nWe observed the field of GRB 210321A (Dichiara  et al., GCN 29677)  with \nAZT-8 telescope of CrAO observatory starting on 2021-03-21 (UT) \n19:04:11. The optical afterglow (Siegel  et al., GCN 29679; Butler et \nal., GCN 29680;   Lipunov et al., GCN 29683; Heintz et al., GCN 29684; \nde Ugarte Postigo et al., GCN 29685; Xin et al. GCN 29687; Pankov et \nal., GCN  29689) is not detected in a combined image. Preliminary \nphotometry of the field  is following\n\nDate       UT start   t-T0       Filter Exp.   OT   Err.  UL(3sigma)\n                       (mid, days)        (s)\n\n2021-03-21 19:04:11   0.51238    R      55*60  n/d  n/d   20.8\n\nThe photometry is based on the nearby USNO-B1.0 stars\nUSNO-B1.0_id R2\n1601-0068003 15.84\n1600-0068970 16.18\n1601-0068018 16.54\n1601-0067995 16.23",
  "circularId": 29692,
  "createdOn": 1616439753000,
  "email": "apozanen@iki.rssi.ru",
  "subject": "GRB 210321A: CrAO optical upper limit",
  "submitter": "Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>",
  "eventId": "GRB 210321A"
}