usage taking account of lunar apogee and perigee requires a more elaborate calculation. Also, due to lunar libration it is not uncommon to see up to 101% of the full moon or even up to 5% of the lunar backside.

Calculating phase size

The phase is equal to the area of the visible lunar sphere that is illuminated by the Sun. This area or degree of illumination is given by , where is the elongation (i.e., the angle between Moon, the observer

1.Previous
3.Next