抚仙湖太阳观测和研究基地知识库

丽江2.4 m望远镜配备的LiJET光谱仪有两种观测模式：DFDI和DEM模式，其中DEM模式可以进行同步定标观测。目前同步定标技术是实现高精度视向速度测量的关键技术之一，而要开展同步定标首先需要评估仪器自身的波长定标精度和仪器稳定情况。由于数据处理软件和流程的不同，极大可能造成数据处理结果的不同，所以针对仪器开发标准化的数据处理程序十分的必要。基于LiJET实测数据，开发了一套针对LiJET的数据处理程序，可以实现图像预处理、光谱级次定位与抽谱等功能。并根据不同精度的大气吸收线丛和钍氩灯标准谱作为参考谱，得出LiJET-DEM模式的波长解和波长定标的精度。而后又在典型的光谱级次使用碘吸收谱验证由钍氩灯得到的定标精度，结果用钍氩灯谱和碘吸收谱独立得到的定标精度接近，分别为3.3×10-4和4.2×10-4 nm。接着也用同一典型光谱级次10 d的钍氩灯谱数据进行仪器稳定分析，其仪器10 d的漂移结果稳定在3.7×10-5 nm,换算成视向速度为19.8 m·s-1。

The LiJET spectrograph equipped with the Lijiang 2. 4-meter telescope has two observation modes:DFDI and DEM mode, of which DEM mode can carry out simultaneous calibration observations. Simultaneously, calibration technology is one of the key technologies used to achieve high-precision radial velocity measurement. To carry out simultaneous calibration, it is necessary to evaluate the wavelength calibration accuracy and instrument stability. The difference in data processing software and processes is very likely to cause a difference in data processing results, so it is necessary to develop standardized data processing procedures for instruments. Based on the measured data of LiJET, a data processing program for LiJET is developed in this paper, which can realize the functions of image preprocessing, spectral order positioning, and spectrum extraction. The wavelength solution and wavelength calibration accuracy of the LiJET-DEM model are obtained by combining atmospheric absorption line cluster, thorium argon lamp spectrum, and other reference spectra. Iodine absorption spectra verify the calibration accuracy obtained by the thorium argon lamp at typical spectral orders. The calibration accuracy obtained by the thorium argon lamp and iodine absorption spectra is close, 3. 3X10-4and 4. 2X10-4nm, respectively. Then, the thorium argon lamp spectrum data of the same typical spectral order for 10 days was used for instrument stability analysis, and the drifting result of the instrument for 10 days was stable at 3. 7X 10-5nm, which was converted to the radial velocity of 19. 8 m. s-1.