NVST多波段光谱仪杂散光研究

发布时间：2018-01-04 12:05

  本文关键词：NVST多波段光谱仪杂散光研究　出处：《中国科学院研究生院(云南天文台)》2016年硕士论文　论文类型：学位论文

  更多相关文章： NVST 多波段光谱仪 杂散光 CaⅡ通道

【摘要】：抚仙湖1m新真空太阳望远镜(New Vacuum Solar Telescope,NVST)是国内口径最大的地基真空太阳望远镜,主要用于太阳光球和色球的高分辨率成像观测和太阳光谱观测[1]。杂散光对成像观测和光谱观测的影响至今都是一个需要解决的难题,光谱观测中,杂散光的能量占光谱强度的很大一部分,会对数据分析结果产生严重影响。当观测目标的亮度越小时,杂散光对其影越大,例如黑子观测、日面边缘观测和较深谱线的观测。地基望远镜杂散光的来源有以下几种:1.由于地球大气中灰尘和粒子的散射而引起的杂散光;2.由于大气折射率的快速变化而产生的在总量上不断变化的杂散光;3.仪器产生的杂散光。我们把多波段光谱仪的杂散光从形式上分为两类来进行研究:一、光谱桶内产生的仪器杂散光,此部分杂散光与进入光谱桶的光强度有关,在入射光强不变的情况下,此部分杂散光为定值,称此部分杂散光为仪器杂散光;二、参与色散的杂散光,是由太阳上观测目标周围的太阳光对观测目标的散射引起的,我们称此部分杂散光为色散杂散光。第一种杂散光可直接测量,约占光谱能量的3%左右。由于许多因素影响第二种杂散光,所以很难精确测量,从日食光谱测量中测得在太阳表面观测目标周围的光经大气散射对观测目标产生的杂散光的下限约在10%。在用抚仙湖1m太阳望远镜多波段光谱仪进行光谱观测时发现,CaⅡ光谱图像在855.6nm吸收线右侧的亮度有肉眼可见的明显下降,针对此现象分析产生光谱图像色散方向上亮度左右差异的原因。分析结果表明,产生此种现象是由于狭缝的次极大衍射光照亮成像镜后反射到CCD,形成了一个弧形的杂散光亮斑,强度约为光谱图像平均强度的20.9%,对CaⅡ通道的光谱图像产生了严重的影响。提出抑制杂散光的方法对其进行消除,使CaⅡ通道杂散光恢复正常水平
[Abstract]:New Vacuum Solar Telescope1 Vacuum is the largest ground-based vacuum solar telescope in China. High resolution imaging and solar spectral observations for solar and color spheres. [1. The influence of stray light on imaging observation and spectral observation is still a difficult problem to be solved. In spectral observation, the energy of stray light accounts for a large part of the spectral intensity. The smaller the brightness of the observed object, the greater the shadow of the stray light, such as the sunspot observation. The sources of stray light for ground-based telescopes are as follows: 1. Stray light caused by dust and particle scattering in the earth's atmosphere; 2. The stray light, which is produced by the rapid change of the refractive index of the atmosphere, is constantly changing in the total amount; 3. The stray light produced by the instrument. We divide the stray light of the multi-band spectrometer into two categories in form: first, the stray light produced in the spectrum barrel. This part of stray light is related to the intensity of the light entering the spectral barrel. When the incident light intensity is constant, this part of the stray light is a fixed value, and this part of the stray light is called the instrument stray light. Second, the stray light involved in the dispersion is caused by the scattering of the solar light around the observed target on the sun. We call this part of the stray light dispersion stray light. The first kind of stray light can be directly measured. It accounts for about 3% of spectral energy. Because of many factors affecting the second stray light, it is difficult to measure accurately. The lower limit of stray light produced by atmospheric scattering around the target observed on the surface of the sun measured from the solar eclipse spectrum measurement is about 10. The spectrum is carried out with the multiband spectrometer of Fuxian lake 1m solar telescope. Observed. The brightness of Ca 鈪，

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