TITLE: GCN GRB OBSERVATION REPORT NUMBER: 473 SUBJECT: GRB 991216, Optical Transient DATE: 99/12/17 16:54:09 GMT FROM: Arne A. Henden at USNO/USRA A. Henden (USRA/USNO), C. Luginbuhl, F. Vrba, H. Harris, B. Canzian, J. Munn, S. Levine, H. Guetter (USNO), D. H. Hartmann (Clemson Univ.), M.C. Jennings (IGPP, UCR visitor) report: We confirm the fading optical source identified by Halpern, et. al (GCN 472). Accurate position from a large set of USNO-A2.0 reference stars is 05:09:31.29 +11:17:07.4 (J2000) (internal error +/- 0.1arcsec) R-band observations, referenced to the star at 05:09:39.30 +11:16:59.5 (J2000) UT r telescope 0409 3.54 1.0-m 0511 3.81 1.3-m 0702 3.87 1.3-m with photometric errors around 0.05mag. It has been non-photometric here for the past few weeks, but as soon as the weather improves, we will calibrate this field in UBVRI. We have additional R-band and V-band data, and will be observing this field again this evening. Our infrared camera went on the 1.55-m this morning, so we may attempt H-band observations as well.