Refraction correction algorithms

Methods for calculating the effect of atmospheric refraction on solar elevation. Some methods account for secondary effects from temperature and pressure.

The following refraction correction algorithms estimate refraction from the true solar (unrefracted) elevation angle:

refraction.archer(elevation)	Atmospheric refraction correction based on the Archer algorithm.
refraction.hughes(elevation[, pressure, ...])	Atmospheric refraction correction based on the Hughes algorithm.
refraction.michalsky(elevation)	Atmospheric refraction correction based on the Michalsky algorithm.
refraction.sg2(elevation[, pressure, ...])	Atmospheric refraction correction based on the algorithm in SG2.
refraction.spa(elevation[, pressure, ...])	Atmospheric refraction correction from the SPA algorithm.

The following refraction correction algorithm calculates refraction from the apparent (refracted) solar elevation:

refraction.bennett(apparent_elevation[, ...])

Atmospheric refraction correction based on the Bennett algorithm.