A&A Supplement series, Vol 121, March 1997, 455-460
Received April 11; accepted June 11, 1996
Send offprint request: J. Kaluzny
Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warsaw, Poland
We present CCD BVI photometry for Berkeley 18, a rich open cluster located in the Galactic anticenter. The cluster age is similar to, or mariginally lower than age of M 67. Its distance is estimated at 5.8 kpc and the reddening E(B-V) is probably higher than 0.46. Our data indicate that Be 18 is one of the most populous objects in the whole sample of known galactic open clusters. The angular diameter of the cluster is estimated at 26 arcmin, which corresponds to a linear size of about 44 pc. The horizontal branch of Be 18 exhibits a large width in comparison with other old open clusters.
keywords: open clusters and associations: individual: Berkeley 18 -- HR diagram