{
  "bibcode": "2005GCN..3845....1H",
  "body": "A. Henden (AAVSO/USNO) reports on behalf of the USNO GRB Team:\n\nWe have acquired BVRcIc all-sky photometry for a 23x23arcmin\nfield centered on the coordinates of the optical afterglow\n(Fox and Cenko, GCN 3829) for the Swift burst GRB050820a\n(Page et al., GCN 3830) with the USNOFS 1.0-m telescope\non one photometric night but with bright moonlight.  Stars\nbrighter than V=12.0 are saturated and should be used with\ncare.  We have placed the photometric data on our anonymous\nftp site:\nftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050820.dat\n\nThe astrometry in this file is based on linear plate solutions\nwith respect to UCAC2.  The external errors are about 100mas.\nThe estimated external photometric error is about 0.03mag.\n\nAs always, you should check the dates on the .dat file prior to\nfinal publication to get the latest photometry.  There is\na README file on the ftp directory to give you information\nabout the procedures used to calibrate these fields.",
  "circularId": 3845,
  "createdOn": 1124642641000,
  "email": "arne@aavso.org",
  "subject": "GRB050820a BVRcIc field photometry",
  "submitter": "Arne A. Henden at AAVSO  <arne@aavso.org>",
  "eventId": "GRB 050820A"
}