ClipArt ETC
"BA is the ray of light passing through a rare medium (as, for instance, air); and upon its entrance into a denser medium (as, for instance, water) the ray will be deflected from the direction of its path BA, and will take the course AE. If the line CD is perpendicular to the dividing surface between the two media, then BAC is the angle of incidence and DAE is the angle of refraction." -Waldo, 1896

Atmospheric Optics

"BA is the ray of light passing through a rare medium (as, for instance, air); and upon its entrance…

The figure "illustrates the bending of the solar rays entering the atmosphere. When the sun is below the horizon, at C, it would be invisible at A, on account of the curvature of the earth, if there were no atmosphere; but the solar rays entering the atmosphere near the point B are refracted so that they reach A, and the sun appears to be at D, though really at C below the horizon, either in the morning or in the evening. So that, in the polar regions, the sun is visible while it is in reality below the horizon, and is thus seen earlier and later during the time of polar sunlight." -Waldo, 1896

Atmospheric Optics

The figure "illustrates the bending of the solar rays entering the atmosphere. When the sun is below…

The halo phenomena is illustrated in this diagram.

Atmospheric Optics

The halo phenomena is illustrated in this diagram.