标题： 为校准建模高分辨率阶梯光谱仪：以Hanle阶梯光谱仪为例 显示英文标题

标题： Modelling high resolution Echelle spectrographs for calibrations: Hanle Echelle spectrograph, a case study

摘要： 我们提出了一种建模方案，该方案能够以高精度预测高分辨率Echelle光谱仪的光谱线特征中心位置。 为此，采用了一种计算方案，使得任何天文光谱仪都可以被建模和控制，而无需依赖光线追迹程序。 这些计算基于近轴光线追迹，并针对某些表面类型和复杂模块的Buchdahl像差系数添加了精确修正。 使用由此产生的所有相关组件的近轴光线追迹和校正链，可以在各种正常运行条件下以高度的确定性计算检测器上任何光谱线的位置。 这将允许使用简单的内部编程模块实现半自主控制。 该方案足够简单，甚至可以在电子表格或任何脚本语言中实现。 我们在此展示了一个Hanle Echelle光谱仪的案例研究。 我们表明我们的结果与流行的商业光线追迹软件的结果非常吻合。 模型进一步通过在仪器初步对齐过程中拍摄的Thorium Argon校准灯曝光进行了优化。 模型预测与校准帧的匹配程度达到了0.08像素。 进行了蒙特卡洛模拟以显示光子噪声对模型预测的影响。 显示英文摘要

摘要： We present a modelling scheme that predicts the centroids of spectral line features for a high resolution Echelle spectrograph to a high accuracy. Towards this, a computing scheme is used, whereby any astronomical spectrograph can be modelled and controlled without recourse to a ray tracing program. The computations are based on paraxial ray trace and exact corrections added for certain surface types and Buchdahl aberration coefficients for complex modules. The resultant chain of paraxial ray traces and corrections for all relevant components is used to calculate the location of any spectral line on the detector under all normal operating conditions with a high degree of certainty. This will allow a semi-autonomous control using simple in-house, programming modules. The scheme is simple enough to be implemented even in a spreadsheet or in any scripting language. Such a model along with an optimization routine can represent the real time behaviour of the instrument. We present here a case study for Hanle Echelle Spectrograph. We show that our results match well with a popular commercial ray tracing software. The model is further optimized using Thorium Argon calibration lamp exposures taken during the preliminary alignment of the instrument. The model predictions matched the calibration frames at a level of 0.08 pixel. Monte Carlo simulations were performed to show the photon noise effect on the model predictions.