In order to reduce the weight and volume of telescope system while remaining high angular resolution

the primary mirror of the two-reflective system is replaced by Golay3 sparse aperture

and the telescope is evaluated and optimized using Zemax sofeware. Firstly a two-reflective system is designed according to third-aberration theory with a spherical primary mirror and a hyperbolic secondary mirror; then the primary mirror is substituted by Golay3 sparse aperture

the relationship between fill factor and sub-mirror’s radius is analyzed

the whole system is simulated by Zemax sofeware to obtain the system’s MTF and the spot diagram. Finally

two Silicon correcting lens are inserted after the secondary mirror to improve the system’s field by optimizing correcting lens’ radius and imaging distances. By Zemax simulation

it is found that the system’s cutoff frequency decreases from 114.5 lp/mm to 97.7lp/mm and to 77.8lp/mm as the fill factor reduces from 22.2% to 15% and to 10%; moreover

the insertion of correcting lens before the image plane can greatly enlarge the system’s field

the RMS value of maximum spot radius without correcting lens is about 2.5 times larger than the one with correcting lens in the field of .