TITLE: GCN GRB OBSERVATION REPORT NUMBER: 299 SUBJECT: GRB990506 observation plan DATE: 99/05/07 23:17:44 GMT FROM: Fredrick J. Vrba at USNO The U.S. Naval Observatory GRB team (F. J. Vrba, C. B. Luginbuhl, A. A. Henden, S. E. Levine, J. Munn, B. Canzian, H. H. Guetter), D. H. Hartmann (Clemson Univ.), and M. C. Jennings (IGPP, UCR visitor) reports that it intends to repeat observations of IPN/RXTE error box for GRB990506 for comparison with data taken 7 May 1999 UT (for pointing and observational details see GCN 294). The data taken 7 May reach an R magnitude of approximately 23-24, and we expect to reach similar limits tonight. If any variable sources are detected, we expect to release the position and approximate photometric measures via GCN by 0700-0800 UT 8 May 1999, which may be sufficient notice for observers located further west.