  We present here our first series in studying the astrophysical parameters of
the open cluster "Ruprecht 15" using PPMXL1 database. In this context, the
photometric, astrometry and statistical parameters for this cluster (limited
radius, core and tidal radii, distances, membership, reddening, age, luminosity
function, mass function, total mass, and the dynamical relaxation time) are
determined for the first time.
