Multicolour CCD measurements of nearby visual double stars. II

We present accurate CCD astrometric and photometric data for 31 nearby visual double stars in the standard filters BVRI. The observations were collected with a 1.3-m telescope in 2001-2002**. The results consist of relative astrometric positions (epoch, angular separation and position angle) and differential BVRI photometry of the components. Mean errors are: 0.01 for the separation; 0.06degrees for the position angle; and 0.(m)015 for the photometric data. Comparing the relative positions at different epochs, we evaluate the physical association of the systems. We additionally derive fractional masses and true separations for the most probable binary systems and, whenever orbits are available, also total and component masses.