Accuracy Analysis of Simultaneous Wavelength Calibration for
LiJET Spectrograph
WANG Jia-qi1, 2, JI Tuo4, CHANG Liang1, 2, 3*
1. Yunnan Observatories, Chinese Academy of Sciences, Kunming 650216, China
2. University of Chinese Academy of Sciences, Beijing 100049, China
3. National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, China
4. Polar Research Institute of China, Shanghai 200136, China
Abstract：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, 3.3×10-4 and 4.2×10-4 nm, 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 3.7×10-5 nm, which was converted to the radial velocity of 19.8 m·s-1.
Key words：Spectrograph; Wavelength calibration; Data processing; Thorium argon lamp
王嘉琦，纪 拓，常 亮. LiJET光谱仪同步波长定标的精度分析[J]. 光谱学与光谱分析, 2025, 45(02): 456-462.
WANG Jia-qi, JI Tuo, CHANG Liang. Accuracy Analysis of Simultaneous Wavelength Calibration for
LiJET Spectrograph. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2025, 45(02): 456-462.
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