A third quarter moon is a primary phase of the lunar cycle that occurs halfway between a full moon and a new moon. It appears as a half-moon, or 50% illuminated, in the sky. However, it is the opposite half compared to a first quarter moon.
Meaning of a third quarter moon
The moon is called ‘third quarter’ because, at that time, it passes three quarters of the way in its orbit around Earth since the new moon.
Rise and set time of a third quarter moon
A third quarter moon rises around midnight, reaches its highest point in the sky (overhead point) around sunrise and sets around noon.
A third quarter moon rises around midnight because it is 270° away from the sun in our sky.
Age of a third quarter moon
A lunar cycle starts with a new moon. Now a third quarter moon appears in the sky about three weeks after a new moon. So a third quarter moon is about 21 days old.
Best time to see a third quarter moon
You’ll find a third quarter moon high in the sky around sunrise.
A third quarter moon is easily visible in the morning, as the sunlight reflected from it is bright enough to be seen against the daytime blue sky.
Duration of a third quarter moon
A third quarter moon has no duration as it occurs at a specific moment in time. It is the moment when the moon passes three quarters of the way in its orbit around Earth.
Orientation of a third quarter moon
A third quarter moon appears as a half-illuminated moon in the sky from anywhere in the world. However, it looks opposite in opposite hemispheres.
The left half of the moon is visible in the Northern Hemisphere, and the right half of the moon is visible in the Southern Hemisphere.
First quarter moon vs. third quarter moon
A first quarter moon appears in the sky about a week after a new moon, whereas a third quarter moon appears in the sky about a week after a full moon.
A first quarter moon is a waxing moon, more precisely called a waxing half moon, whereas a third quarter moon is a waning moon, more precisely called a waning half moon.
The terminator—the line that divides light and dark—of a first quarter moon shows sunrise on the moon, whereas the terminator of a third quarter moon shows sunset on the moon.
The phases of the moon
The moon goes through phases as it orbits Earth. Follow the links below to understand the phases of the moon.
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