Department of Mathematical Physics, Torino University, Torino, Italy
2 Torino Astronomical Observatory, Strada Osservatorio 20, I-10025 Pino Torinese, Torino, Italy
3 Department of Astronomy, Padova University, vicolo dell'Osservatorio 5, I-35122 Padova, Italy
Send offprint request to: G. Carraro
Accepted: 11 June 1996
A colour magnitude diagram (CMD) extending to mag is given for 444 stars in the region of the galactic cluster Berkeley 66. The and I photometry of a nearby field is also reported. This object appears very faint, highly contaminated by foreground stars and very reddened. The apparent distance modulus and the colour excess EV-I are guessed to be 17.5 and 1.1, respectively, with an uncertainty of at least 30%. Adopting these values the comparison of the CMD with theoretical isochrones from the Padova group provides an age around 1.0 Gyr.
Key words: open clusters: Berkeley 66 / HR diagram
© European Southern Observatory (ESO), 1997