We present moes, a ray tracing software package that computes the path of rays through echelle spectrographs. Our algorithm is based on sequential direct tracing with Seidel aberration corrections applied at the detector plane. As a test case, we model the CARMENES VIS spectrograph. After subtracting the best model from the data, the residuals yield an rms of 0.024 pix, setting a new standard for the precision of the wavelength solution of state-of-the-art radial velocity (RV) instruments. By including the influence of the changes of the environment in ray propagation, we are able to predict instrumental RV systematics at the 1 m/s level.

中文翻译：

---

中阶梯光栅光谱仪的光线追踪应用于波长解决方案以实现精确的径向速度

我们推出了 moes，一种光线追踪软件包，可以计算通过中阶梯光栅光谱仪的光线路径。我们的算法基于顺序直接追踪，并在探测器平面上应用赛德尔像差校正。作为测试用例，我们对 CARMENES VIS 摄谱仪进行建模。从数据中减去最佳模型后，残差产生 0.024 像素的均方根值，为最先进的径向速度 (RV) 仪器的波长解决方案的精度设立了新标准。通过考虑环境变化对射线传播的影响，我们能够预测 1 m/s 水平的仪器 RV 系统。