一米新真空红外太阳望远镜多波段光谱仪光谱弯曲分析

An Analysis of Spectrum Curvatures for the Multi-Wavelength Spectrometer of the New Vaccum Solar Telescope of the Yunnan Observatories

在太阳长狭缝光谱观测中,光谱的狭缝方向和色散方向应该分别与CCD探测器的两个边缘平行。但实际上,由于狭缝、光栅、CCD探测器的机械安装精度等原因,会造成他们之间的位置关系不匹配,导致得到的太阳光谱总是存在一定的倾斜和变形。即使有时这些倾斜很微小,也会对太阳光谱的平场计算造成严重影响,从而影响整个光谱数据的处理过程。对抚仙湖1 m新真空红外太阳望远镜多波段光谱仪得到的一组Hα光谱数据的倾斜量做了测量和分析,并讨论了其对太阳光谱平场计算的影响。

In observation of long-slit solar spectra, the slit direction and dispersion direction of a spectrum should ideally be parallel to two sides of the CCD, respectively. In practice this is difficult to be achieved because of errors of the relative positions of the slit, grating grooves, and the detector as introduced in installation of the mechanisms. Observed solar spectra are then always curved （or inclined）. The purpose of this paper is to measure and analyze the curvatures of Hα solar spectra obtained by the Multi-Wavelength Spectrometer of the new vaccum solar telescope of the Yunnan Observatories. We also discuss influences of spectral curvatures on evaluation of flatfields.