Ma Donglin
Opt Express. 2018 Jan 8;26(1):108-119. doi: 10.1364/OE.26.000108.
Recently, China is planning to construct a new large optical-infrared telescope (LOT), in which the aperture of the primary mirror is as large as 12m. China's LOT is a general-purpose telescope, which is aimed to work with multiple scientific instruments such as spectrographs. Based on the requirements of LOT telescope, we have compared the performance of Ritchey-Chrétien (RC) design and Aplanatic-Gregorian (AG) design from the perspective of scientific performance and construction cost. By taking the primary focal ratio, Nasmyth focal ratio, and telescope's site condition into consideration, we finally recommend a RC f/1.6 design configuration for LOT's Nasmyth telescope system. Unlike the general identical configuration, we choose a non-identical configuration for the telescope system which has a shorter Cassegrain focal ratio compared to the designed Nasmyth focal ratio. The non-identical design can allow for a shorter back focal distance and therefore a shorter telescope fork to guarantee the gravitational stability of the whole telescope structure, as well as relatively lower construction cost. Detailed analysis for the feasibility of our recommended design is provided in this paper.
最近，中国正计划建造一台新的大型光学红外望远镜（LOT），其主镜口径达12米。中国的LOT是一台通用望远镜，旨在与光谱仪等多种科学仪器配合使用。基于LOT望远镜的要求，我们从科学性能和建造成本的角度比较了里奇-克莱琴（RC）设计和消球差格里高利（AG）设计的性能。考虑到主焦比、纳氏焦比和望远镜的台址条件，我们最终为LOT的纳氏望远镜系统推荐了一种RC f/1.6设计配置。与一般的相同配置不同，我们为望远镜系统选择了一种非相同配置，其卡塞格伦焦比比设计的纳氏焦比短。这种非相同设计可以实现更短的后焦距，从而使望远镜叉臂更短，以保证整个望远镜结构的重力稳定性，同时建造成本也相对较低。本文对我们推荐设计的可行性进行了详细分析。
