It is the astigmatism that leads the traditional imaging spectrometer based on Czerny-Turner to have low spatial
resolution. And it is discovered that when the distance between concave mirror and grating, <i>x</i>, is equal to the twice of
focal length, ƒ, of the mirror, S<sub>II</sub> = S<sub>III</sub> = 0 and the aberration is the least as well as the astigmatism is eliminated greatly.
Meanwhile the toroidal mirror is presented to correct the astigmatism, and as well the aberration caused by the large
FOV is corrected by optimizing the surface tilt. Then both of the spatial and spectral resolutions are improved. Finally a
Czerny-Turner imaging spectrometer working in FUV (120 nm ~ 180 nm) with 2.5° FOV is designed, and its focal
length is 147.61 mm, its F number is 3.93. MTF of this imaging spectrometer is more than 0.39 at 20 lp/mm in the total
wavelength band of FOV, which satisfied the requirements of imaging spectrometer working on satellite in FUV.
The far ultraviolet scanning imaging spectrometer (FUSIS) is used to measure the composition and distribution of the
main molecules and atoms in the Earth's upper atmosphere. It is an important instrument in investigation of the physical
and chemical processes in the Earth's upper atmosphere. FUSIS works between 120nm to 180nm, its spectral resolution
is better than 1.0nm and its spatial resolution is 8 pixels. This paper describes a kind of ground calibration method and
facility of FUSIS. The FUV light is invisible, so all works must be done in high vacuum. The calibration facility includes
the FUV light source, collimator, and the vacuum chamber. The pumps of vacuum system can debase the pressure down
to 5×10<sup>-5</sup>Pa. Calibration experiments are accomplished in the vacuum chamber. The spectral calibration of FUSIS is
achieved with the linear interpolation method. The radiation transfer function is deduced. But some factors in the
function such as reflection components' reflectivity and detector's quantum efficiency are hard to test accurately. So we
use a radiation correction matrix instead of the transfer function in practice. Assuming the FUSIS instrument is a blackbox,
the matrix can be tested by experiments. FUSIS can get the absolute radiation intensity of target by calling the
This article describes the characteristics of the far ultraviolet (FUV) radiation and its applications in the space weather's
research and prediction. The FUV imaging spectrometer is irreplaceable to get the FUV radiation data of the earth's
upper atmosphere. Some key technologies of FUV spectrometer are analyzed respectively, including window materials,
FUV light source, FUV detectors and FUV coating, which offer theoretical foundation for FUV imaging spectrometer.
The paper presents a FUV band imaging spectrometer's optical system which is based on crossed Czerny-Turner
structure with all reflective components in it. The wavelength range of the FUV spectrometer optical system is from
100nm to 200nm and the initial structure is simulated and optimized by Zemax in order to improve the spectral
resolution. The theoretical spectral resolution of the system is better than 1nm, and it has a certain imaging capacity.