The general equations of the path of a ray of light passing through the terrestrial atmosphere are outlined. The path of the ray tangent to the earth’s surface is calculated for the U. S. Standard Atmosphere. From this is prepared a table of horizon dip, horizon distance, and refraction for altitudes from sea level to 100,000 feet.
JOHN SWEER, "The Path of a Ray of Light Tangent to the Surface of the Earth," J. Opt. Soc. Am. 28, 327-327 (1938)