2022/04/06 by Luc Dettwiller, Dettwiller, Luc · 1 citation
Engineering · #Advanced Measurement and Metrology Techniques #Astronomical Observations and Instrumentation #Calibration and Measurement Techniques #FOS: Physical sciences #Instrumentation and Methods for Astrophysics (astro-ph.IM) #Optics (physics.optics)
paper · pdf · doi:10.48550/arxiv.2204.02603
openalex publication_date 2022/04/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The empirical law of Gladstone-Dale is insufficient for high-precision studies using the refractivity of a gas: this is not exactly proportional to its density, and the gas may not be properly described as perfect. An optical Mariotte temperature allows making a comparative analysis of the results given by various authors. The effect of hygrometry on the refractivity at visible wavelengths is historically traced and its small effect on the astronomical refraction angle numerically shown. Finally at infrared and radio wavelengths, the effects of the humidity in the lower atmosphere can be strong; as for the ionosphere, its curvature plays an essential role for the astronomical refraction angle unlike in the visible.