{
  "bibcode": "2017GCN.21387....1K",
  "body": "Y. Kitaoka, T. Sakamoto (AGU)\n\nWe observed the field of GRB 170728B detected by Swift (Cenko et al., GCN Circ. 21371)\nwith the iTelescope.Net (http://www.itelescope.net) T16 (Takahashi TOA-150) telescope\nlocated at the AstroCamp Observatory (Nerpio, Spain).  20 images of 60 sec exposures\nwere taken in the R filter starting from July 28  23:03:19 (UT) about  36 mimute after\nthe trigger and stopped on July 29 00:17:48 (UT).  We do not detect the optical afterglow\nboth in the individual images and the stacked image at the X-ray afterglow position.\nThe estimated five sigma upper limit of the combined image (total exposure of 1200 sec)\nis ~15.8 using the USNO-B1 catalog.",
  "circularId": 21387,
  "createdOn": 1501370348000,
  "email": "tsakamoto@phys.aoyama.ac.jp",
  "subject": "GRB 170728B iTelescope observation",
  "submitter": "Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>",
  "eventId": "GRB 170728B"
}