TITLE:   GCN CIRCULAR
NUMBER:  646
SUBJECT: GRB 000418, Optical Observation
DATE:    00/04/25 23:00:23 GMT
FROM:    Nestor Mirabal at Columbia U.  <abulafia@astro.columbia.edu>

N. Mirabal, J. P. Halpern, J. Kemp, & D. J. Helfand (Columbia U.)
report on behalf of the MDM Observatory GRB follow-up team:

"The potential K-band counterpart of GRB 000418 reported by
Klose et al. (GCN #645) is present in an R-band image which
we obtained on the MDM 2.4m telescope on April 21, 03:33 UT.
Its position is (J2000) RA 12 25 19.30, Dec. +20 06 11.1,
with an uncertainty of 0."5.  Under non-photometric conditions
we measure R = 21.52 +/- 0.12 for this candidate, referenced
to a USNO star at (J2000) RA 12 25 25.62, Dec. +20 04 57.8 which
is listed as R = 15.4.  An additional systematic uncertainty
of 0.2 mag should be assumed based on the dispersion among
other USNO star magnitudes in this field.

Further observations are needed to determine if this object
is fading.

This message may be cited."