Berkeley 22 , an old and distant open cluster towards the Galactic anticentre

We present deep CCD BV I photometry of the distant, old open cluster Berkeley 22, covering from the red giants branch (RGB) to about 6 magnitudes below the main sequence (MS) turn-off. Using the synthetic Colour Magnitude Diagram method with three different types of stellar evolutionary tracks, we estimate values and theoretical uncertainty of distance modulus (m-M)0, reddening E(B−V ) , age τ and approximate metallicity. The best fit to the data is obtained for 13.8 ≤ (m-M)0≤ 14.1, 0.64 ≤ E(B − V ) ≤ 0.65, 2.0 ≤ τ ≤ 2.5 Gyr (depending on the amount of overshooting from convective regions adopted in the stellar models) and solar metallicity.