本文關(guān)鍵詞：NVST多波段光譜儀雜散光研究　出處：《中國科學(xué)院研究生院(云南天文臺(tái))》2016年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： NVST 多波段光譜儀 雜散光 CaⅡ通道

【摘要】：撫仙湖1m新真空太陽望遠(yuǎn)鏡(New Vacuum Solar Telescope,NVST)是國內(nèi)口徑最大的地基真空太陽望遠(yuǎn)鏡,主要用于太陽光球和色球的高分辨率成像觀測和太陽光譜觀測[1]。雜散光對(duì)成像觀測和光譜觀測的影響至今都是一個(gè)需要解決的難題,光譜觀測中,雜散光的能量占光譜強(qiáng)度的很大一部分,會(huì)對(duì)數(shù)據(jù)分析結(jié)果產(chǎn)生嚴(yán)重影響。當(dāng)觀測目標(biāo)的亮度越小時(shí),雜散光對(duì)其影越大,例如黑子觀測、日面邊緣觀測和較深譜線的觀測。地基望遠(yuǎn)鏡雜散光的來源有以下幾種:1.由于地球大氣中灰塵和粒子的散射而引起的雜散光;2.由于大氣折射率的快速變化而產(chǎn)生的在總量上不斷變化的雜散光;3.儀器產(chǎn)生的雜散光。我們把多波段光譜儀的雜散光從形式上分為兩類來進(jìn)行研究:一、光譜桶內(nèi)產(chǎn)生的儀器雜散光,此部分雜散光與進(jìn)入光譜桶的光強(qiáng)度有關(guān),在入射光強(qiáng)不變的情況下,此部分雜散光為定值,稱此部分雜散光為儀器雜散光;二、參與色散的雜散光,是由太陽上觀測目標(biāo)周圍的太陽光對(duì)觀測目標(biāo)的散射引起的,我們稱此部分雜散光為色散雜散光。第一種雜散光可直接測量,約占光譜能量的3%左右。由于許多因素影響第二種雜散光,所以很難精確測量,從日食光譜測量中測得在太陽表面觀測目標(biāo)周圍的光經(jīng)大氣散射對(duì)觀測目標(biāo)產(chǎn)生的雜散光的下限約在10%。在用撫仙湖1m太陽望遠(yuǎn)鏡多波段光譜儀進(jìn)行光譜觀測時(shí)發(fā)現(xiàn),CaⅡ光譜圖像在855.6nm吸收線右側(cè)的亮度有肉眼可見的明顯下降,針對(duì)此現(xiàn)象分析產(chǎn)生光譜圖像色散方向上亮度左右差異的原因。分析結(jié)果表明,產(chǎn)生此種現(xiàn)象是由于狹縫的次極大衍射光照亮成像鏡后反射到CCD,形成了一個(gè)弧形的雜散光亮斑,強(qiáng)度約為光譜圖像平均強(qiáng)度的20.9%,對(duì)CaⅡ通道的光譜圖像產(chǎn)生了嚴(yán)重的影響。提出抑制雜散光的方法對(duì)其進(jìn)行消除,使CaⅡ通道雜散光恢復(fù)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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