CAJ | 학술논문

光纤的焦比退化（focal ratio degradation）是光纤光谱效率损失的重要原因之一。光纤在安装和每次定位过程中，光纤的转动和扭曲会引起光纤焦比退化发生变化，从而改变光纤的传输效率，每根光纤由此造成的传输效率变化都会存在差异。而这样的效率差异无法用通常天文观测中使用的晨昏天光平场或者圆顶平场改正。减天光是光纤光谱数据处理中决定光谱质量的重要环节。减天光处理要求对不同光纤的传输效率进行归一化处理，以扣除不同光纤之间传输效率差异导致的天光背景测量的误差。对于与天光背景亮度接近乃至更暗的观测目标而言，光纤传输效率的改正精度决定了减天光的精度。测试了LAMOST望远镜光纤转动对光纤传输效率的影响情况。在检查了光谱中天光发射线强度与光纤传输效率的关系，和验证了光纤效率变化与波长变化相对独立的基础上，提出并且证实了通过测量各光纤中天光发射线强度作为光纤相对效率变化量来改正光纤效率差异的方法是可行的。这种方法已经被应用到LAMOST二维光谱处理当中。
광섬적초비퇴화（focal ratio degradation）시광섬광보효솔손실적중요원인지일。광섬재안장화매차정위과정중，광섬적전동화뉴곡회인기광섬초비퇴화발생변화，종이개변광섬적전수효솔，매근광섬유차조성적전수효솔변화도회존재차이。이저양적효솔차이무법용통상천문관측중사용적신혼천광평장혹자원정평장개정。감천광시광섬광보수거처리중결정광보질량적중요배절。감천광처리요구대불동광섬적전수효솔진행귀일화처리，이구제불동광섬지간전수효솔차이도치적천광배경측량적오차。대우여천광배경량도접근내지경암적관측목표이언，광섬전수효솔적개정정도결정료감천광적정도。측시료LAMOST망원경광섬전동대광섬전수효솔적영향정황。재검사료광보중천광발사선강도여광섬전수효솔적관계，화험증료광섬효솔변화여파장변화상대독립적기출상，제출병차증실료통과측량각광섬중천광발사선강도작위광섬상대효솔변화량래개정광섬효솔차이적방법시가행적。저충방법이경피응용도LAMOST이유광보처리당중。
The focal ratio degradation (FRD) of optical fiber is one of major sources causing light loss in multi‐fiber astronomical instruments .Meanwhile ,the sky subtraction is crucial to multi‐fiber spectra reduction ,especially for the objects which are as faint as the sky background ,not to mention for those even fainter ones .To improve the accuracy of sky subtraction ,it is neces‐sary to normalize the throughput among object fibers and sky sampling fibers .The rotation and twist during mounting and rota‐ting could change the FRD of individual fibers ,which means the variation of the transmission throughput among fibers .We in‐vestigate such throughput variation among LAMOST fibers and its correlation with the intensity of sky emission lines on all wavelength coverage in this paper .On the basis of this work ,we present an approach to correcting the varied fiber throughput by measuring the intensity of the sky emission lines as the secondary throughput correction .This approach has been applied to LAMOST 2D Pipeline .