TITLE: GCN GRB OBSERVATION REPORT NUMBER: 578 SUBJECT: GRB 000301C, Optical Observation DATE: 00/03/04 01:33:27 GMT FROM: Jules Halpern at Columbia U. J. P. Halpern, N. Mirabal, & S. Lawrence (Columbia U.) report on behalf of the MDM Observatory GRB follow-up team: "We imaged the location of GRB 000301C as determined by the intersection of the RXTE All-Sky Monitor error box and the Ulysses/NEAR annulus (Smith, Hurley, & Cline, GCN #568) in the R band on March 3.51 UT using the MDM 1.3m telescope. The optical transient found by Fynbo et al. (GCN #570,576) is measured at R = 20.24 +/- 0.05, referenced to the comparison stars of Garnavich et al. (GCN #573). This is consistent with measurements by Garnavich et al. and Veillet (GCN #575) that were obtained contemporaneously. The implied power-law decay index is still rather uncertain. Using our magnitude and that measured by Fynbo et al. (GCN #576), we find alpha = -1.56 +/- 0.30. This predicts R = 20.90 +/- 0.18 on March 4.51 UT. We measure the position of the optical transient to be (J2000) RA 16:20:18.550, Dec +29:26:35.96 relative to 30 USNO-A2.0 stars having a dispersion of 0".31 in radius. CCD images are posted at http://www.astro.bio2.edu/grb/ This message may be cited."