DETERMINE THE EFFECTIVE PARAMETERS IN GRAVITATIONAL LENSES AND STUDY THE ALTERNATIVE EFFECTS BETWEEN THEM

Abstract

The importance of the gravitational lens in cosmology and astronomy, and a briefhistorical review for the evolution of the gravitational lenses have been introduced. The effectiveparameters are determined by using the geometrical model of the Point mass gravitational lens. A studyof the effective strength of the geometrical distances ,the source and the lens distances , the distancebetween the lens and the source ,and the impact parameter in the distance from the source to the image.By using the variation of the image distance with respect to the geometrical distance . We concludedthat the strengths effect of these parameters approaching zero at very large distances, except that ofthe distance between the lens and the source which seems to be constant. This kind of behavior hasbeen explained .