Stellar Proper Motions can be represented as great circles over the Celestial Sphere. This point of view creates a geometry over the sphere where the study of parallelism of the motions is possible in an easy form. Calculus of intersections between circles can detect convergence point of motions. This means parallel spatial motion. The model can be carried out to open stars clusters, identifying convergence points as apex, in order to get membership probabilities or, in a general form, to stars of our galaxy to detect big stellar structures and to infer some details about their kinematics. We present here a short description of the model and some examples using stars of the Hipparcos catalogue.