TITLE: GCN GRB OBSERVATION REPORT NUMBER: 653 SUBJECT: GRB 000418, Optical Observation DATE: 00/04/28 13:51:38 GMT FROM: Nestor Mirabal at Columbia U. N. Mirabal, J. P. Halpern (Columbia U.), R. M. Wagner (Ohio State U.) report on behalf of the MDM Observatory GRB follow-up team: "We obtained additional R-band images of the afterglow candidate for GRB 000418(Klose et al., GCN #645) using the MDM 2.4m telescope. The object located at (J2000) RA 12:25:19.30, Dec. +20:06:11.1 has an estimated magnitude R = 22.8 +/- 0.31 on April 28.3 UT, this magnitude is referenced to USNO star (J2000) RA 12:25:25.62, Dec +20:04:57.8 (R = 15.4). The decline is consistent with the -0.84 +/- 0.2 power-law derived from previous detections (Mirabal et al., GCN #646,#650). In addition we note that the OT appears to be slightly extended which might be an indication of residual light from an underlying host galaxy. This message may be cited."