The proper motions were represented by a kind of 'adaptive' model, using a three dimensional expansion in a series of orthogonal functions of galactic latitude, longitude and of the logarithm of the distance. Our programme searches automatically for significant functions. Most of the found significant functions belong to exact or approximate equivalents of known standard motions, especially the average ensemble motion and the two first order parameters of galactic rotation. Beyond these standard motions, three non-standard functions appear. These figures agree with those of nearby old giants, but they now refer to a much larger volume and number of stars.
All dispersions depend on the distance z perpendicular to the galactic plane.
Most distinctly, the dispersion perpendicular to the galactic plane cannot be described by one isothermal component. Thus at least 3 components would be required if a description with isothermal components were wanted. I describe the outlines of a project aimed at characterising the binary population in the nearby OB Associations. The distribution of observations giving the smallest errors for specific purposes is found in the general case by a numerical procedure. Examples consider the minimum error ellipse for the recovery of a distant asteroid, a main belt object and the position in the target plane for a close approach to the Earth.