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We analysed the open clusters Czernik 2 and NGC 7654 using CCD UBVphotometric and Gaia Early Data Release 3 (EDR3) photometric and astrometricdata. Structural parameters of the two clusters were derived, including thephysical sizes of Czernik 2 being r=5 and NGC 7654 as 8 min. We calculatedmembership probabilities of stars based on their proper motion components asreleased in the Gaia EDR3. To identify member stars of the clusters, we usedthese membership probabilities taking into account location and the impact ofbinarity on main-sequence stars. We used membership probabilities higher than$P=0.5$ to identify 28 member stars for Czernik 2 and 369 for NGC 7654. Weestimated colour-excesses and metallicities separately using two-colourdiagrams to derive homogeneously determined parameters. The derived $E(B-V)$colour excess is 0.46(0.02) mag for Czernik 2 and 0.57(0.04) mag for NGC 7654.Metallicities were obtained for the first time for both clusters, -0.08(0.02)dex for Czernik 2 and -0.05(0.01) dex for NGC 7654. Keeping the reddening andmetallicity as constant quantities, we fitted PARSEC models usingcolour-magnitude diagrams, resulting in estimated distance moduli and ages ofthe two clusters. We obtained the distance modulus for Czernik 2 as 12.80(0.07)mag and for NGC 7654 as 13.20(0.16) mag, which coincide with ages of 1.2(0.2)Gyr and 120(20) Myr, respectively. The distances to the clusters werecalculated using the Gaia EDR3 trigonometric parallaxes and compared with theliterature. We found good agreement between the distances obtained in thisstudy and the literature. Present day mass function slopes for both clustersare comparable with the value of Salpeter (1955), being X=-1.37(0.24) forCzernik 2 and X=-1.39(0.19) for NGC 7654.

A study of the Czernik 2 and NGC 7654 open clusters using CCD UBV photometric and Gaia EDR3 data