{
  "bibcode": "2017GCN.21805....1M",
  "body": "E. Mazaeva (IKI),  E. Chornaya (UAFO), A. Pozanenko (IKI), A. Volnova \n(IKI), A. Matkin (UAFO), I. Molotov (KIAM)  report on behalf of  larger \nGRB follow-up collaboration:\n\nWe observed the field of  Swift GRB 170903A  (Markwardt et al., GCN \n21793) with SANTEL-650 (0.65m)  telescope  of UAFO/ISON-Ussuriysk \nobservatory. We obtained several unfiltered images starting on  Sep. 03 \n(UT) 13:20:15.  Within enhanced XRT position (Goad et al., GCN 21797) we \ndo not detect any source.  Preliminary photometry of a combined image is \nfollowing\n\nDate       UT start  t-T0     Filter  Exp.      OT   Err.  UL\n                     (mid, days)       (s)\n\n2017-09-03 13:20:15  0.04847  CR      120*30    n/d  n/d   20.4\n\n\nPhotometry is based on nearby SDSS DR9 stars\nSDSS_DR9_id         R(Lupton)\nJ165744.06+345751.4 16.01\nJ165803.01+345725.1 16.56\nJ165808.53+350159.7 15.58\nJ165749.08+345655.1 16.66\nJ165805.88+345230.1 16.24",
  "circularId": 21805,
  "createdOn": 1504522907000,
  "email": "apozanen@iki.rssi.ru",
  "subject": "GRB 170903A: UAFO /ISON optical upper limit",
  "submitter": "Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>",
  "eventId": "GRB 170903A"
}