一个大型光学/红外望远镜方案的研究

STUDY OF A LARGE OPTICAL/IR TELESCOPE SCHEME

基于中国目前已具备生产最大口径为2.16米光学望远镜的能力,本文从理论上研究了一个由多个2.16米望远镜构成的望远镜阵方案的可行性.以6个望远镜呈正六边形分布,工作在光学及红外波段的望远镜阵作为一个实例.它有三个工作模式:1)单望远镜工作;2)非相干合成,其等效集光口径为5.29米,文中给出了一个由光导纤维联接望远镜主焦点的设计方案;3)相干合成(即综合孔径),最大基线长度为100米。文中还给出了一个具体的设计方案.

In this paper, the study of a scheme of a large telescope array is presented. As an example, a large telescope scheme consisting of six 2.16m telescopes, based on the 2.16m optical telescope completed in the last year, is studied. It can be operated both in visible and IR wavelength regions in three modes: 1. as unit 2.16m telescope which can be operated at the prime focus, Cassegrain focus and Coude focus; 2. as an incoherent array for visible wavelength region; 3. as a phased array. In section two, a preliminary design for an incoherent telescope array is given. Six fibers each with a length of about 20m and a core diameter of 65μ are used to link the prime focus and the beam transfer system. Six fibers are also used to guide the light beam to a common detector. The techniques of improving the transmittance of the system, are described. In section three, the relation between the optical path difference (OPD) compensation and the obtainable phased field of view (FOV) ate discussed first. Then, a scheme of coherent telescope array is studied in three aspects: the distribution of the telescopes, beam transfer and optical delay line, and beam combination. The advantages and disadvantages of the coherent telescope array with large aperture at visible wavelengths are discussed. At last, we point out the advantages of the telescope array we proposed in this paper in the technological, economical and astronomical efficiency points of view.