TITLE: GCN GRB OBSERVATION REPORT NUMBER: 458 SUBJECT: GRB 991208, Optical Observation DATE: 99/12/13 15:25:48 GMT FROM: Jules Halpern at Columbia U. J. P. Halpern & D. J. Helfand (Columbia U.) report on behalf of the MDM Observatory GRB follow-up team: "We imaged the field of GRB 991208 in the R band on Dec. 13.53 UT using the MDM 2.4m telescope. A single 10 minute exposure was obtained in non-photometric conditions. The seeing was 1.1 arcseconds. The afterglow was detected at R = 20.92 +/- 0.06, referenced to the comparsion star quoted in GCNs 454 and 456 as having R = 15.9. The decay index between our measurement and that of Garnavich & Noriega-Crespo one day earlier (GCN 456) is -1.9 +/- 0.4. This message may be cited."