All-spherical Catadioptric system for 0.8 m F/4.5 astronomicaltelescope: can we compete with the Ritchey-Chretien design?

摘要

Aspherical surfaces are difficult to manufacture, therefore we consider a possibility of using only spherical surfaces. Two optical designs for 800-mm F/4.5 seeing limited telescope are considered: Ritchey-Chretien and a two-mirror Catadioptric system. The Ritchey-Chretien system has a hyperboloidal primary mirror, a planoid aspheric secondary mirror, and a two-lens field corrector, whereas the all-spherical system contains a Mangin mirror and a meniscus corrector as the secondary group and a three-lens corrector. Our analysis of the image quality achieved in the two designs shows that the all-spherical catadioptric system is an acceptable alternative to the Ritchey-Chretien design.