Characteristic analysis of Golay 6 multiple-mirror telescope

Abstract

Sparse aperture telescopes represent a promising technology for increasing the effective diameter of an optical system while reducing the weight and the size. Multiple-mirror telescope (MMT) and multiple-telescope telescope (MTT) are two types of sparse aperture systems. The primary mirror of MMT consists of a number of segments that are all parts of a single primary-mirror conic. The configuration of the sparse aperture is related to the performance of the MMT. Golay configuration is nonredundant sparse aperture. Entrance pupil characteristics of Golay 6 MMT are studied to research the relationships between the sub-mirrors on the primary mirror and the shapes of sub-apertures on the entrance pupil of Golay 6. Overlay factor and efficiency factor are proposed to achieve the optimal fill factor on the entrance pupil. Given the relative aperture of Golay 6 MMT, there is some concern that the fill factor on the entrance pupil is larger than the overlay fill factor on the spherical sparse aperture primary mirror. The maximum fill factor and the maximal overlay factor are discussed, and the tangency condition when sub-mirrors of Golay 6 MMT are tangency is derived. Two Cassegrain telescopes having a spherical primary mirror with Golay6 configuration and with an aspherical secondary mirror are designed. The fill factor on the entrance pupil can be larger than the overlay factor on the primary mirror at the certain occasion. Based on the relationships between the fill factor and the overlay factor, the rational parameters of sub-mirrors on the primary mirror can be selected.