Potentialities, for Image Evaluation, of Geometric Ray Trace Focal Plots

Abstract

The formulas of Robert E. Hopkins, University of Rochester, Rochester, New York, giving resolving power as a function of certain image “energy” diameters have been applied to geometric focal plots of an f/4.7, 36-inch focal length Parabolic Reflector and the Hopkins designed Elgeet Navitar lens for the CZR-1 Bowen Camera. The formula $R=605({d_e}^2+{d_f}^2{)}^{-\frac{1}{2}}$ gives the resolution R in lines/mm; d_e represents the diameter of the circle containing 30% of the energy in the image, and d_f is a constant of the emulsion, both expressed in microns. The parameter d_e was obtained by direct measurements on focal plots of the geometric ray traces, and the resulting resolving powers were confronted with corresponding measured values. The comparison, so far, has been confined to Super XX and reveals the limited nature and over-all conservatism of the method.