{
  "bibcode": "2021GCN.30263....1J",
  "body": "M. Jelinek, J. Strobl, R. Hudec, C. Polasek (ASU CAS Ondrejov)\nreport:\n\nWe observed the position of the bright GRB 210420B (D'Avanzo et al., GCN\n30261) with the D50 telescope of the Astronomical Institute Ondrejov, near\nPrague, Czech Republic. We performed a series of unfiltered exposures\nstarting 23:59:53 UT, between 28 s and 2 h after the trigger.\n\nThe optical afterglow (Lipunov et al., GCNC30259 & 30262) is clearly\ndetected in single images. We can confirm a decaying nature of the object -\nthe afterglow faded to r'(AB)~17.7 mag during the course of our\nobservations, which were ended by twillight 2.0h after the trigger. The\nalpha decay by the  end of observations was ~0.6, indicating a possible\nplateau phase.",
  "circularId": 30263,
  "createdOn": 1624157233000,
  "email": "martin.jelinek@asu.cas.cz",
  "subject": "GRB 210619B: Ondrejov D50 detection",
  "submitter": "Martin Jelinek at Astro.Inst-AVCR,Ondrejov  <martin.jelinek@asu.cas.cz>",
  "eventId": "GRB 210619B"
}