Design and wavefront sensing for the segmented spherical primary optical telescope

On account of the tight requirement of the high-resolution, the Segmented Primary Optical Telescope (SPOT) becomes the mainstream. Obviously, the use of a strongly aspheric form creates several intractable problems in manufacturing and subsequent optical testing of aspheric off-axis segments having different forms, the task of controlling a large number of aspheric segments for on-orbit cophasing is formidable, so the prospect of assembling the primary mirror from small, low-cost identical spherical mirror segments is very attractive. This paper will discourse upon the demand of the SPOT and analyze the advantages of segmented spherical primary mirror relative to aspheric. Besides these, the author will design an optical systems under the properties (D=1200mm, MTF ≥ 0.6), the optical designs use a full steerable, quasi-Cassegrain telescope in which the primary mirror uses spherical surface, then we will demonstrate its performance and prove the practicality of Spherical Primary Optical Telescope. Ultimately, we will introduce a multistage wavefront sensing and control strategy briefly for Diffraction-limited phasing.