Quasi-concentric mirror arrangement, e.g. for telescope - has small scattering mirror with central hole which reflects light onto collector mirror, and is anastigmatic

摘要

The mirror arrangement has a collector mirror which reflects light onto a smaller scattering mirror which reflects light back to the collector mirror. The optical axes of the two mirrors coincide, and the scattering mirror has a central hole. The scattering mirror is placed between the collector mirror and its focal point. The radius of the scattering mirror is such that slightly divergent light from it is reflected back from the collector mirror. The mirror arrangement is aplanar and anastigmatic, and the deformation of the two mirrors is hyperbolic. A scattering mirror can be chosen to form a Ritchey-Chretien telescope. USE/ADVANTAGE - Telescope for astronomy. Allows simultaneous correction of spherical aberration and astigmatism of mirror arrangement. Uses only two aspherical mirrors.