  We conducted a photometric and astrometric study of three open stellar
clusters (Collinder 467, Dolidze 18, and Ruprecht 70), which have not been
photometrically studied before. The most important thing for using Gaia (DR2)
database lies in the positions, parallax, and proper motions, which make us
split cluster members from the field ones and get precise astrophysical
parameters. On studying the radial density profiles of the clusters under
study, the actual sizes are estimated and found larger using Gaia. From the
color-magnitude diagrams and theoretical isochrones, we simultaneously
determined the ages, distance moduli, and reddening of the clusters. However,
considering the parallaxes of Gaia DR2 for the cluster members, we calculated
the cluster distance and confirmed what we obtained from the color-magnitude
diagram. Then, the Cartesian galactocentric coordinates (Xsun, Ysun, Zsun), and
the distances from the galactic center (Rg) were also estimated. According to
luminosity and mass functions, the total luminosity and total mass of the
clusters are estimated. Our study shows that Collinder 467 is dynamically
relaxed, and Ruprecht 70 has recently relaxed, while Dolidze 18 is not relaxed
yet.
