{
  "bibcode": "2018GCN.23206....1V",
  "body": "A. Volnova  (IKI),  A. Pozanenko (IKI), R. Inasaridze (AbAO),  E. \nMazaeva (IKI),  V. Ayvazian  (AbAO),  O. Kvaratskhelia (AbAO), G. \nKapanadze (AbAO),  I. Molotov (KIAM) report on behalf of larger GRB \nfollow-up collaboration:\n\nWe observed the field of the Swift GRB 180904A (D'Ai et al., GCN 23194) \nwith AS-32 (0.7m) telescope of Abastumani Observatory starting on \nSeptember 04 (UT) 21:52:23.   We do not detect any object within \nenhanced XRT position (Osborne et al., GCN 23196). Preliminary \nphotometry of the field is following:\n\nDate        UT start   t-T0      Filter Exp.   OT    Err. UL\n                      (mid, days)        (s)\n\n2018-09-04  21:52:23   0.05731   CR     70*60  n/d   n/d  21.5\n\nThe photometry is based on nearby USNO-B1.0 stars (R2 magnitude)\nUSNO-B.1_id    R2\n1366-0296056   14.72\n1366-0296068   15.43\n1365-0287325   15.62\n1366-0296106   15.21\n1366-0296088   14.95\n1366-0296093   14.37",
  "circularId": 23206,
  "createdOn": 1536164302000,
  "email": "apozanen@iki.rssi.ru",
  "subject": "GRB 180904A: AbAO optical upper limit",
  "submitter": "Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>",
  "eventId": "GRB 180904A"
}