The major variation in the brightness of the Moon is due to it's phase. When the Moon is a  "New Moon" it is lined up on the same side of the Earth as the Sun, so we see only the un-illuminated side of the Moon. Approximately 14 days later, it is on the opposite side of the Earth from the Sun, and every portion of the Moon that we can see is illuminated. This is the "Full Moon".

Lunar Brightness with Phase Angle

Untitled photo
Powered by SmugMug Owner Log In