According to sparrow criterion, two point sources are said to be resolved when the second derivative of the total distribution of irradiance in the diffracted image of the two- points, vanishes at a point midway between the respective Gaussian image points. When this condition is satisfied, the distance between the two object points gives the sparrow limit of resolution. In the resultant irradiance distribution curve, the central dip just vanishes when the resolution begins. Initially the dip is at the middle point between the two Gaussian image points when the separation between two point object is larger than the critical limit. As the distance between the points is reduced, the dip reduces in its upward concavity and it just vanishes at a particular separation of the two point objects.