摘要: While large aperture telescopes are highly desirable for their enormous light grasp, smaller telescopes are increasingly pressed into service as wide-field survey instruments to aid in the search for near earth objects, satellites... 展开 While large aperture telescopes are highly desirable for their enormous light grasp, smaller telescopes are increasingly pressed into service as wide-field survey instruments to aid in the search for near earth objects, satellites and space debris. Various optical designs are found throughout the technical literature but not all represent truly capable wide-field survey instruments and the search to find such designs is time consuming without any guarantees of its completeness. Here we present an overview of wide-field optical designs suitable for survey instruments in the 1/2 meter class aperture range. The size is small enough to be affordable for many less well funded research programs, yet large enough that when coupled with a modest CCD mosaic, the resulting system represents a capable survey instrument. Many optical designs exist with each having its own strengths and limitations. 收起