  We present the observations of the binary lensing event MACHO-98-SMC-1
conducted at the Mt.~Stromlo 74" telescope by the Microlensing Planet Search
(MPS) collaboration. The MPS data constrain the first caustic crossing to have
occurred after 1998 June 5.55 UT and thus directly rule out one of the two fits
presented by the PLANET collaboration (model II). This substantially reduces
the uncertainty in the the relative proper motion estimations of the lens
object.
  We perform joint binary microlensing fits of the MPS data together with the
publicly available data from the EROS, MACHO/GMAN and OGLE collaborations. We
also study the binary lens fit parameters previously published by the PLANET
and MACHO/GMAN collaborations by using them as initial values for $\chi^2$
minimization. Fits based on the PLANET model I appear to be in conflict with
the GMAN-CTIO data. From our best fit, we find that the lens system has a
proper motion of $\mu = 1.3\pm 0.2 \kmsk$ with respect to the source, which
implies that the lens system is most likely to be located in the Small
Magellanic Cloud strengthening the conclusion of previous reports.
