TITLE: GCN GRB OBSERVATION REPORT NUMBER: 518 SUBJECT: GRB991216, UBVRIJHK field photometry DATE: 00/01/14 19:03:19 GMT FROM: Arne A. Henden at USNO/USRA A. Henden (USRA/USNO), H. Guetter and F. Vrba (USNO) report on behalf of the USNO GRB team: We have acquired UBVRcIc all-sky photometry for the field of GRB991216 with the USNOFS 1.0-m telescope on four photometric nights, but with some nights having poor seeing. This field is reddened, with a mean color (B-V) ~ 1.2. Because of this, many of the fainter sources do not have U or B magnitudes. We have therefore created two files on our anonymous ftp site: ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb991216.dat ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb991216f.dat where the first file contains multicolor observations, and the second file contains a smaller set of fainter stars surrounding the OT position, but with only R magnitudes listed. In particular, the R magnitudes we obtain for stars A and B of Jha (GCN 476) and the comparison star of Henden (GCN 463) agree with those obtained by Dolan, et. al. (GCN 486) within the quoted errors. The astrometry in these files is based on linear plate solutions with respect to USNO-A2.0. The internal errors are less than 100mas. We also observed this field with the USNO IRCAM on the 1.55-m telescope on a single photometric night to obtain JHK photometry for 6 stars near the OT position. Observations were obtained of 11 standard stars to put the measures on the CIT photometric system. The errors reflect uncertainties in the in the extinction and color transformations. The data were reduced independently in K and H magnitudes and J-H and H-K colors: RA (J2000) DEC K H J-H H-K 77.375279 11.288480 11.77+/-.03 11.92+/-.03 0.69+/-.03 0.19+/-.03 77.374150 11.285729 12.48 .03 12.62 .03 0.70 .04 0.19 .03 77.392377 11.290707 14.00 .04 14.19 .03 0.82 .04 0.27 .03 77.399284 11.290875 14.68 .08 14.85 .10 0.50 .10 0.25 .10 77.377129 11.297201 14.61 .07 14.65 .05 0.61 .04 0.11 .05