{
  "bibcode": "2000GCN...518....1H",
  "body": "A. Henden (USRA/USNO), H. Guetter and F. Vrba (USNO)\nreport on behalf of the USNO GRB team:\n\nWe have acquired UBVRcIc all-sky photometry for the field\nof GRB991216 with the USNOFS 1.0-m telescope on four\nphotometric nights, but with some nights having\npoor seeing.  This field is reddened, with\na mean color (B-V) ~ 1.2.  Because of this, many of\nthe fainter sources do not have U or B magnitudes.  We have\ntherefore created two files on our anonymous ftp site:\nftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb991216.dat\nftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb991216f.dat\nwhere the first file contains multicolor observations, and\nthe second file contains a smaller set of fainter stars\nsurrounding the OT position, but with only R magnitudes\nlisted.  In particular, the R magnitudes we obtain for\nstars A and B of Jha (GCN 476) and the comparison\nstar of Henden (GCN 463) agree with those obtained by\nDolan, et. al. (GCN 486) within the quoted errors.\nThe astrometry in these files is based on linear plate\nsolutions with respect to USNO-A2.0.  The internal errors\nare less than 100mas.\n\nWe also observed this field with the USNO IRCAM on the\n1.55-m telescope on a single photometric night to obtain\nJHK photometry for 6 stars near the OT position. Observations\nwere obtained of 11 standard stars to put the measures on the\nCIT photometric system. The errors reflect uncertainties in the\nin the extinction and color transformations. The data were\nreduced independently in K and H magnitudes and J-H and H-K\ncolors:\n\nRA (J2000)     DEC           K          H          J-H       H-K\n77.375279   11.288480  11.77+/-.03 11.92+/-.03 0.69+/-.03 0.19+/-.03  \n77.374150   11.285729  12.48   .03 12.62   .03 0.70   .04 0.19   .03\n77.392377   11.290707  14.00   .04 14.19   .03 0.82   .04 0.27   .03 \n77.399284   11.290875  14.68   .08 14.85   .10 0.50   .10 0.25   .10\n77.377129   11.297201  14.61   .07 14.65   .05 0.61   .04 0.11   .05",
  "circularId": 518,
  "createdOn": 947876599000,
  "email": "aah@nofs.navy.mil",
  "subject": "GRB991216, UBVRIJHK field photometry",
  "submitter": "Arne A. Henden at USNO/USRA  <aah@nofs.navy.mil>",
  "eventId": "GRB 991216"
}