Design of a zoom telescope optical system with a large aperture, long focal length, and wide field of view via a catadioptric switching solution

Abstract

This study presents a catadioptric switching solution for a zoom telescope optical system to achieve a large aperture, long focal length, and wide field of view. The proposed optical system combines a Newton-type main system with a collimator group and a switching zoom group. Furthermore, clear imaging of long and short focal lengths under different operating ranges and temperatures is realized using a moving collimator group. For the field of view at both long and short focal lengths, the modulation transfer function exceeds 0.5 at the Nyquist frequency, 80% of the energy is concentrated in a diameter of 0.025 mm (i.e., less than two pixels), and the maximal distortion is 0.962%. The presented switching-zoom system exhibits high imaging quality for each focal length as well as a simple structure and stable performance.