Abstract:
We present U BV RI CCD photometry of three open star clusters
Be 15, Be 71 and King 1 for the first time. Base on these data, optical colour-
magnitude diagrams (CMDs) for the stars in the clusters down to V = 22 mag
are studied. There are 1408, 1887 and 2485 stars located in the regions of Be 15,
Be 71 and King 1 respectively. We also provide estimates of their fundamental
parameters such as radius, reddening, distance and age. The radius values for
the clusters Be 15, Be 71 and King 1 are 4.5, 3.0 and 4.0 arcmin respectively.
The corresponding distances are 3.0±0.3,3.9±0.4 and 1.9±0.2 kpc respectively
while the ages are log (age)=8.5±0.1, 8.8±0.1 and 9.2±0.1 respectively. The
red giant clump is clearly visible in the CMDs of cluster King 1.
