TITLE: GCN GRB OBSERVATION REPORT NUMBER: 163 SUBJECT: GRB 981220 Optical Observations DATE: 98/12/23 09:41:29 GMT FROM: Jules Halpern at Columbia U. J. Halpern & E. Gotthelf (Columbia U.), C. Martin & B. Kern (Caltech), report: "We obtained a 600 s R-band image of the joint RXTE/IPN error region of GRB 981220 (GCN 159,160) on the Palomar 5m telescope on Dec 23.15. The limiting magnitude was about 22.7. Preliminary analysis shows no new object in comparison with the digitized POSS II plate to a limit of R=20.5. Our image is posted at http://www.astro.columbia.edu/~evg/grb981220.html" This message may be cited. [GCN OP NOTE: 28mar99: The ".edu" was added to the URL.]