IMAGE BEHAVIOR OF OPTIC POSITIONED INSIDE THE DIFFRACTIVE DEPTH OF FOCUS

Standard diffractive estimates based on the system fl# were at odds wi th geometric predictions concerning beam footprint size at a relayed p upil image plane due to an object point at infinity. The reason for th is was that the relay optic was well within the defractive depth of fo cus of an intermediate star image. This invalidated geometric predicti ons for the system fl # and the location and size of the system impuls e response. Accurate predictions emerged when Fourier transforms of th e highly apodized planar wavefront incident on the relay optic were ca lculated.