8th The Sun-Earth-Moon System (C20) Practice Test

As the Moon orbits Earth, its illuminated portion wanes from Full Moon toward New Moon. The sequence after a Full Moon goes through Waning Gibbous, then the half-illuminated Third Quarter, then Waning Crescent before reaching New Moon. Halfway in that interval is the Third Quarter, the point at which exactly half of the Moon’s near side is lit. In the Northern Hemisphere this looks like the left half illuminated, and it occurs about seven days after the Full Moon and seven days before the New Moon.