Waning Moon:Third Week Halfway through its cycle, the whole near side of the Moon is in sunlight : a full moon. You might think of it as the second quarter.Viewed from Earth, the Moon and the Sun are in opposite directions.If you face a full moon at sunset, sunlight from behind you lights the back of your head and the near side of the Moon.As the Moon continues around during the third week, less and less of the near side is in sunlight. The Moon seems to shrink, or wane, so these phases are called waning gibbous moons.