{
  "bibcode": "2021GCN.30320....1V",
  "body": "J. Vinko, L. Kriskovics, A. Pal, R. Szakats, K. Vida, Zs. Szabo, R. Konyves-Toth, M. Krezinger and K. Sarneczky (Konkoly Observatory, Hungary) report:\n\nWe observed the field of GRB210619B\n(D'Avanzo et al.,GCN #30261, #30288, #30289; Jelinek et al., GCN #30263, #30281;\nLipunov et al., GCN #30259; Zhao et al., GCN #30261; Kong et al.,\nGCN #30265; Axelsson et al., #GCN 30270; de Ugarte Postigo et al.,\nGCN #30272; Zheng et al., GCN #30273; Blazek et al., GCN #30274;\nKann et al., GCN #30275; Svinkin et al., GCN #30276; Xin et al.,\nGCN #30277; Perley et al., GCN #30271, Shrestha et al., GCN #30280,\nKumar et al. GCN #30286; Cunningham et al., GCN #30290; Romanov,\nGCN #30291; Hu et al., GCN #30293; Zhu et al., GCN #30294;\nBelkin et al., GCN #30299; Atteia, GCN #30301, Minaev et al.,\nGCN #30304; Romanov & Lane, GCN #30305; Karpov et al., GCN #30308;\nMoskvitin & Maslennikova, GCN #30309; Marisaldi et al., GCN #30315)\nwith the RC80 robotic telescope at Piszkesteto Station of Konkoly\nObservatory on 2021 June 22 starting at 22:46:41.5 UT. A series of 5x300 sec\nframes were collected through Sloan r'- and i' bands. The optical afterglow\nwas detected with the following magnitudes calibrated via nearby PS1 stars:\n\nDate         UT-middle   t-T0(hr)  Exp(s)   r'(mag)           i'(mag)\n2021-06-22   23:07:16    71.13     5x300    21.454 +/-0.333   20.089 +/-0.280\n\nFollow-up observations on 2021-06-23 starting at 21:34:37.7 UT (3.90 days post-trigger)\nresulted in no detection down to limiting magnitudes of r'=22.14 and i'=21.98 mag.",
  "circularId": 30320,
  "createdOn": 1624658062000,
  "email": "vinko@konkoly.hu",
  "subject": "GRB210619B: optical afterglow detection from Konkoly Observatory",
  "submitter": "Jozsef Vinko at Konkoly Observator  <vinko@konkoly.hu>",
  "eventId": "GRB 210619B"
}