The SOLIS Integrated Sunlight Spectrometer

The SOLIS Integrated Sunlight Spectrometer (ISS) is designed
to obtain both high (R = 300,000) and moderate (R = 30,000) spectral resolution
observations of the Sun as a star. ISS provides observations of disk-integrated
sunlight through the use of a fiber optic feed. A small optical system utilizing
a lens of 8-mm diameter will focus a 400 micron diameter image of the Sun on the
input face of the fiber. The output beam from the fiber will consist of sunlight
scrambled in both angle and position so that any output angle from any position
on the exit face will be well-integrated. A prism pre-disperser will isolate
the desired wavelength band. The McPherson 2-m Czerny-Turner spectrograph in
the ISS employs a 316 g/mm grating blazed at 63.5 degrees. The focal plane
detector is a movable, back-illuminated 1024 X 256 CCD. Among the many
wavelengths measured are the Ca II H and K lines at 396.8 and 393.4 nm,
He I 1083 nm, H-alpha 656.3 nm, and the Ca II triplet at 854.2 nm.

SOLIS综合日光光谱仪（Integrated Sunlight Spectrometer，简称ISS）旨在获取太阳作为恒星的高（R = 300,000）和适中（R = 30,000）光谱分辨率观测。ISS通过光纤馈送的方式提供对日面整体光照的观测。一个直径为8毫米的透镜组成的小型光学系统，将直径为400微米的太阳图像聚焦于光纤的输入面。光纤的输出光束将在角度和位置上产生杂乱，使得从出口面任何位置的输出角度都将得到良好的综合。一个预先色散的棱镜将隔离所需的光谱波段。ISS中的McPherson 2米Czerny-Turner光谱仪采用了一个63.5度闪耀的316线/mm的光栅。焦平面探测器是一个可移动的、背面照明的1024 X 256 CCD。在测量的众多波长中包括Ca II H和K线（396.8和393.4纳米）、He I线（1083纳米）、H-α线（656.3纳米）以及Ca II三重线（854.2纳米）。