{
  "bibcode": "2017GCN.21169....1M",
  "body": "E. Mazaeva (IKI), K. Antonyuk (CrAO), I. Nikolenko (CrAO), V. Rumyantsev \n(CrAO),  A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of larger \nGRB follow-up collaboration:\n\nWe observed the field of the GRB 170519A (Ukwatta et al., GCN 21106)\nwith AZT-11 telescope of CrAO observatory starting on May 19 (UT)\n19:07:44, and with Zeiss-1000/Koshka telescope of Simeiz branch of CrAO\nobservatory starting on May 19 (UT) 19:28:57. We took several images in \nfilter R with exposures of 180 s. We clearly detect the afterglow \n(Ukwatta et al., GCN 21106; Izzo et al., GCN 21108) in combined images.\n\nPreliminary photometry of the combined images is following\n\nUT start    t-T0   Filter       Exp.     OT      err    UL    Telescope\n            (mid, days)       (s)                       (3sigma)\n\n\n19:07:44   0.58810\tR\t6*180    19.17   0.11   20.9  AZT-11\n19:26:08   0.59878\tR\t4*180    19.23   0.12   20.7  AZT-11\n19:41:28   0.61473\tR\t9*180    19.58   0.12   21.1  AZT-11\n19:28:57   0.59751\tR\t1*180    19.05   0.10   20.4  Zeiss-1000\n19:31:58   0.60066\tR\t2*180    19.12   0.10   21.1  Zeiss-1000\n19:38:02   0.60592\tR\t3*180    19.52   0.14   20.3  Zeiss-1000\n19:47:08   0.61224\tR\t3*180    19.52   0.16   20.3  Zeiss-1000\n19:56:13   0.62065\tR\t5*180    19.64   0.14   21.3  Zeiss-1000\n\nThe photometry is based on nearby SDSS stars:\n\nSDSS-DR9_id\t    R(Lupton)\nJ105339.53+252259.9 17.32\nJ105332.97+252127.3 16.22\t\t\nJ105348.21+252041.2 17.03\t\t\t\nJ105341.14+252534.0 16.18\t\t\t\t\nJ105353.70+252400.0 15.30",
  "circularId": 21169,
  "createdOn": 1496176435000,
  "email": "apozanen@iki.rssi.ru",
  "subject": "GRB 170519A: CrAO optical observations",
  "submitter": "Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>",
  "eventId": "GRB 170519A"
}