{
  "bibcode": "2021GCN.29570....1J",
  "body": "Martin Jelinek, Jan Strobl, Rene Hudec and Cyril Polasek (ASU CAS Ondrejov,\nCZ), report:\n\nThe 0.2 m Small Binocular Telescope (BART/SBT) of Ondrejov observatory in\nCzech republic reacted robotically to the alert of GRB 210226A (Beardmore\net al, GCNC 29568), obtaining a series of 12 s unfiltered images starting\nat 04:54:55.8 UT, i.e. 659 s post trigger.\n\nWe do not detect any new source within the XRT errorbox neither in single\nimages (3-sigma limit r'(AB) > ~14.0) nor in a combined 30 x 12 s frame\n(mean exp time 1033 s post trigger, 3-sigma limit r'(AB) > ~15.8) as\ncalibrated against the Atlas catalog (Tonry et al. ApJ 867, 105, 2018).",
  "circularId": 29570,
  "createdOn": 1614326759000,
  "email": "martin.jelinek@asu.cas.cz",
  "subject": "GRB 210226A: Ondrejov BART/SBT optical limit",
  "submitter": "Martin Jelinek at Astro.Inst-AVCR,Ondrejov  <martin.jelinek@asu.cas.cz>",
  "eventId": "GRB 210226A"
}