1.绪言大多放大型天文望远镜都可以做成各种观测样式变焦距形式。目前使用的多数望远镜是Newtonian—Cassegrain式的,插入二次双曲面镜,或用在抛物面镜的主焦点,或用在主镜后形成的Cassegrain或Coude焦点处。最近正在制造的Ritchey—Chretien 1. Introduction Most of the magnifying telescopes can be made into various forms of observation zoom. Most of the telescopes currently in use are Newtonian-Cassegrain type, with the insertion of a hyperboloid or primary focus on a parabolic mirror or at the Cassegrain or Coude focal point created after the primary mirror. Recently manufactured Ritchey-Chretien