Since the absorption of ultraviolet radiation in the atmosphere is strong, it is difficult to image solar UV
radiation using ground-based telescopes. While, the moon which has no atmosphere and has stability
geological structure and low magnetic field, observing the sun on the moon is more suitable than observing
the sun on the earth. This paper describes the design of lunar-based solar telescope which can image the sun
in three wavelength: long-wave IR (8-12μm), visible (400-900nm) and UV(100-400nm). The telescope is
mainly composed of two parts: reflective telescope and splitting system. This design effectively avoids the
material restrictions of IR and UV imaging optical systems. The rationality of the optical system design of
the common aperture multi-wavelength telescope was proved by comparing the results with the images get
by single wavelength solar telescopes all over the world. Compared the images took under different weather,
the importance of the proposition of lunar-based devise is proved. Combined the splitters and the spectral
response range of detectors, the UV, visible and IR can be split and imaged by different detectors.
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, x, is equal to the twice of
focal length, , of the mirror, SII = SIII = 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 5×10-5Pa. 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
matrix.
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