云南天文台1m望远镜暗天体分光仪和照相机

Faint Object Spectrograph and Camera for 1m Telescope

云南天文台1m望远镜终端之一的暗天体分光仪和照相机具有4种运行模式:缩焦照相机、无缝多目标光谱仪、有缝光谱仪和星冕仪。这4种运行模式能在几分钟的时间内相互转换,高效快速和灵活方便。该仪器的光学质量优秀,光学系统消像差,特别是消色差。由于光学系统消色差,所成像的低色散光谱在404.6～766.5nm全波段尖锐平直。在多色测光时,各测光波段的像面位置不变,同时兼有大视场的优点,可提高测光精度和测光效率。

A Faint Object Spectrograph and Camera (FOSC) for 1-meter telescope in Yunnan Observatory is introduced in this paper.It is a focal reduced camera type instrument and is mounted at the Cassegrain focus of 1-m telescope in Yunnan Observatory.The FOSC can be used in four different modes:direct imaging,long slit spectroscopy,slitless spectroscopy and coronography,and it is efficient and flexible.The optics design for the camera and for the spectrograph are shown.The light from the f/13.3 Cassegrain focus of the 1-m telescope is collimated by collimating lens then passes to the camera and images on the CCD detector.In the wavelegth range of 404.6nm-766.5nm, the image quality is 0.5″ in diameter which encircles 80% of the energy in the 10′ of the field.Four modes are as follows:1Direct Imaging:It is a focal reduced camera with a field of 10′.The focal ratio is f/7.The standard filters of B?V?R?I are mounted for selection.2Slitless Spectroscopy Mode:A direct vision prism is inserted into the parallel beam of the focal reduced camera to become a slitless spectroscopy.The dispersion of this slitless spectroscopy is 100nm/mm in 486.1nm.3Long Slit Spectroscopy:The long slits are available to do spectroscopy with the direct vision prism.There are three slits mounted on a wheel in the Cassegrain focus.The slit size is 40mm×65μm(～1″),40mm×100μm(～1.5″),40mm×150μm(～2.25″),respectively.4Coronography Mode:A special plate is mounted on the slits wheel which is in the area of Cassegrain focus.The coronograph image can be obtained and the faint nebulosity around bright objects would be imaged with this mode.