AI 中文总结
本研究利用MagAO-X系统实时测量残余大气色散并反馈至ADC进行闭环控制，将残余色散降至亚毫角秒每微米水平，为极大望远镜的系外行星高对比度成像提供关键技术支撑。
AI 中文摘要
来自太空真空的入射星光进入地球大气层时会发生折射。大气折射的波长依赖性会导致地面望远镜的宽带点扩散函数（PSF）发生拉伸，尤其在可见光波段。这会导致图像质量下降，同时日冕仪的挡光效率降低，两者均限制了高对比度观测。大气色散校正器（ADC）是一种用于补偿该效应的色散光学元件。当前的色散补偿方法使用分析模型，根据台站海拔、望远镜天顶角等参数预测色散强度；然而，色散强度还受沿恒星视线方向无法测量的诸多因素影响，包括瞬时湿度、温度和气压，这会导致ADC对真实大气色散的校正始终过度或不足。本研究使用拉斯坎帕纳斯天文台的麦哲伦极端自适应光学系统MagAO-X，实时测量并校正残余大气色散。残余色散的量编码在卫星斑的取向中，该卫星斑通过将MagAO-X的变形镜用作衍射光栅产生。我们已将这些实时测量结果作为反馈，对ADC进行闭环控制，在可见光和近红外（NIR）波段的天空观测中，将残余大气色散降低至小于1毫角秒每微米（sub-mas/μm）的水平。MagAO-X上的主动大气色散校正在即将到来的极大望远镜（Extremely Large Telescopes）上的极端自适应光学高对比度成像中是一项先导技术，这类观测需要高精度的色散补偿以成像反射光中的系外行星。
英文摘要
Incoming starlight is refracted as it enters Earth's atmosphere from the vacuum of space. The wavelength-dependence of atmospheric refraction causes elongation of the broadband PSF of ground-based telescopes, especially in the visible spectrum. The result is degraded image quality alongside reduced coronagraph light-blocking efficiency, both of which limit high-contrast observations. An atmospheric dispersion corrector (ADC) is a dispersive optic used to compensate for this effect. Current methods for dispersion compensation use analytical models to anticipate dispersion strength based on parameters such as site altitude and telescope zenith angle; however, dispersion strength is also dictated by a number of factors that cannot be measured, including instantaneous humidity, temperature, and pressure along the line of sight to the star. This leads to constant over- or under-correction of the true atmospheric dispersion by the ADC. In this work, we use the Magellan extreme adaptive optics system MagAO-X at Las Campanas Observatory to measure and correct residual atmospheric dispersion in real-time. The amount of residual dispersion is encoded in the orientation of satellite spots generated by using MagAO-X's deformable mirror as a diffraction grating. We have used these real-time measurements as feedback for closed-loop control of the ADCs on-sky at visible and NIR wavelengths, reducing residual atmospheric dispersion down to sub-mas/$μ$m levels. Active atmospheric dispersion correction on MagAO-X is a precursor to high-contrast imaging with Extreme AO for the upcoming Extremely Large Telescopes, where high-precision dispersion compensation will be required to image exoplanets in reflected light.
Comments12 pages, 8 figures, proceedings of SPIE Astronomical Telescopes + Instrumentation 2026
