Abstract
We present CCD photometry of the galactic open clusters NGC 2658, NGC 2849, and NGC 3247. By means of the comparison between the observed cluster sequences and the Padova theoretical isochrones, we derive the following parameters: for NGC 2658, E(B-V) =0.35+0.05-0.10 , log(age) = 8.50+0.25-0.05, and (m - M)0 = 13.32+0.36-0.52; for NGC 2849, the reddening is in the range 0.46 to 0.57 with an uncertainty of +/-0.12 mag, (m - M)0 = 14.02+0.38-0.40, and log(age) = 8.8+0.1-0.05; finally, for NGC 3247 we obtain E(B-V)=0.39±0.07 , log(age) = 7.60+0.4-0.3, and (m - M)0 = 11.89+0.51-0.45. In this study the isochrones have been renormalized to the solar values (B-V)⊙ =0.65 and M[V] = 4.84; the values ( {V-R)⊙ =0.37 and (V-I)⊙ =0.70 are proposed as zero points in order to renormalize those colors as well.
