Aperture configuration and imaging performance

It is generally accepted for optical apertures that obstructions of small proportions are relatively harmless for good imaging performance and that larger aperture obstructions should be avoided. This work presents some quantitative data on this subject. Optical simulation was used to measure parameters of images created by different families of aperture configurations. Twenty-four apertures were selected, and the following data given: aperture shape, energy portion within an area equivalent to the Airy disk and to a circle including the third bright ring of the ideal diffraction image, modulation transfer function, and a photograph of the diffraction image. Design criteria are discussed for aperture configurations of large telescope systems.