{
  "bibcode": "2017GCN.21203....1M",
  "body": "E. Mazaeva (IKI),  R. Inasaridze (AbAO), A. Pozanenko (IKI), A. Volnova \n(IKI),  V. Ayvazian  (AbAO),  O. Kvaratskhelia (AbAO), G. Inasaridze \n(AbAO), I. Molotov (KIAM), report on behalf of larger GRB follow-up \ncollaboration:\n\nWe observed the field of the Swift  GRB 170604A (Page et al., GCN 21191) \n  with AS-32 (0.7m) telescope of Abastumani Observatory starting on \nJune, 04 (UT)  23:52:07. We obtained several unfiltered images of the \nfield.   Within enhanced XRT error circle  (Page et al., GCN   21196) we \ndetected the afterglow (Izzo et al, GCN 21192; Izzo et al, GCN 21197; \nSchady, , GCN 21200). Preliminary photometry of the afterglow is following\n\nDate        UT start   t-T0     Filter Exp.   OT   Err UpLim (3 sigma)\n                       (mid, days)       (s)\n\n2017-06-04 23:52:07   0.19950   CR     5*60  19.13 0.18  21.0\n2017-06-05 00:00:50   0.20675   CR     7*60  19.23 0.16  21.1\n2017-06-05 00:13:02   0.21885   CR    13*60  19.30 0.22  20.6\n\nPhotometry is based on nearby USNO-B1.0 stars (R2 magnitudes)\nUSNO-B.1_id    R2\n0746-0830331 14.71\n0746-0830367 14.76\n0746-0830438 15.14\n0746-0830455 14.77\n0747-0821123 14.60\n\n[GCN OPS NOTE(05jun17):  Per author's request, the duplicate text\nof this circular was removed.]",
  "circularId": 21203,
  "createdOn": 1496677711000,
  "email": "apozanen@iki.rssi.ru",
  "subject": "GRB 170604A: AbAO optical observations",
  "submitter": "Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>",
  "eventId": "GRB 170604A"
}