Here we assess the spectral and imaging properties of Fabry Pérot etalons when located in solar magnetographs. We discuss the chosen configuration (collimated or telecentric) for both ideal and real cases. For the real cases, we focus on the effects caused by the polychromatic illumination of the filter by the irregularities in the optical thickness of the etalon and by deviations from the ideal illumination in both setups. We first review the general properties of Fabry Pérots and we then address the different sources of degradation of the spectral transmission profile. We review and extend the general treatment of defects followed by different authors. We discuss the differences between the point spread functions (PSFs) of the collimated and telecentric configurations for both monochromatic and (real) quasi-monochromatic illumination of the etalon. The PSF corresponding to collimated mounts is shown to have a better performance, although it varies from point to point due to an apodization of the image inherent to this configuration. This is in contrast to the (perfect) telecentric case, where the PSF remains constant but produces artificial velocities and magnetic field signals because of its strong spectral dependence. We find that the unavoidable presence of imperfections in the telecentrism produces a decrease of flux of photons and a shift, a broadening and a loss of symmetrization of both the spectral and PSF profiles over the field of view, thus compromising their advantages over the collimated configuration. We evaluate these effects for different apertures of the incident beam.
Broadband stability of the Habitable Zone Planet Finder Fabry-Pérot etalon calibration system: evidence for chromatic variation
白光照明的法布里-珀罗标准具的梳状光谱可以作为精确多普勒测量的成本效益和稳定的参考。了解这些器件在其宽光谱带宽（100 nm）范围内的稳定性对于实现其作为多普勒校准器的全部潜力至关重要。然而，公开的描述仍然限于小带宽或短时间跨度。我们提出了一个$\sim6$月的宽带稳定性监测活动的法布里-珀罗标准具系统部署的近红外宜居带行星光谱仪（HPF）。我们监测的$\sim3500$谐振模式中的每一个的波长测量HPF光谱的法布里-珀罗标准具（自由光谱范围= 30 GHz，带宽= 820 - 1280纳米），利用电光频率梳参考的准确性和精度。这些结果揭示了色结构的法布里-珀罗模式的位置，并在其随时间的演变。我们测量的平均漂移为2 cm s $^{-1}$ d $^{-1}$，局部偏差高达$\pm5$ cm s $^{-1}$ d $^{-1}$。我们讨论了这些行为的背景下的法布里-珀罗标准具镜色散和其他光学性质的系统，以及使用类似的系统进行精确的多普勒测量的影响。我们的结果表明，该系统支持HPF的波长校准在$\lesssim10$ cm s $^{-1}$水平超过一夜，并在$\lesssim30$ cm s $^{-1}$水平超过$\sim10$ d。我们的研究结果还强调了需要长期和光谱分辨的类似系统，将部署到支持多普勒测量精度接近$\sim10$厘米秒$^{-1}$的研究。
Characterization of telecentric dual-etalon Fabry-Pérot systems from observational data. Properties of the CRISP2 instrument at the Swedish 1-m Solar Telescope
Institute for Solar Physics, Dept. of Astronomy, Stockholm University, AlbaNova University Centre（斯德哥尔摩大学太阳物理研究所天文学系阿尔巴诺瓦大学中心）
BTFI2: a simple, light and compact Fabry-Perot instrument for the SOAR telescope
我们提出了一个新的法布里-珀罗仪器的概念，称为BTFI-2，这是基于另一个巴西仪器的SOAR望远镜，巴西可调滤波成像仪（BTFI）的设计。BTFI-2被设计安装在智利Cerro Pachón的SOAR望远镜上的SOAR自适应模块设施的访问端口上。该光学法布里-珀罗仪器的视场为3 x 3弧分，每像素0.12弧秒，光谱分辨率为4500和12000，在H-α下，由两个可用的ICOS法布里-珀罗设备决定。在需要大面积空间分辨率的情况下，该仪器将是研究正常、相互作用和活动星系中心以及星系间介质的唯一仪器。BTFI-2将结合之前两种仪器（SAM-FP和BTFI）的最佳功能：它将使用电子倍增探测器进行低速度和快速扫描，它将有可能使用新的法布里-佩罗标准具，该标准具提供一系列分辨率，并且它足够轻，可以连接到SAM上工作，因此输出数据立方体将经过GLAO校正。
