A first quarter moon is a primary phase of the lunar cycle that occurs halfway between a new moon and a full moon. It appears as a half-moon, or 50% illuminated, in the sky.
Meaning of a first quarter moon
The moon is called ‘first quarter’ because, at that time, it passes a quarter of the way in its orbit around Earth since the new moon.
Rise and set time of a first quarter moon
A first quarter moon rises around noon, reaches its highest point in the sky (overhead point) around sunset and sets around midnight.
A first quarter moon rises around noon because it is 90° away from the sun in our sky.
Age of a first quarter moon
A lunar cycle starts with a new moon. Now a first quarter moon appears in the sky about a week after a new moon. So a first quarter moon is about 7 days old.
Best time to see a first quarter moon
You’ll find a first quarter moon high in the sky around sunset.
A first quarter moon is easily visible in the afternoon, as the sunlight reflected from it is bright enough to be seen against the daytime blue sky.
Duration of a first quarter moon
A first quarter moon has no duration as it occurs at a specific moment in time. It is the moment when the moon passes a quarter of the way in its orbit around Earth.
Orientation of a first quarter moon
A first quarter moon appears as a half-illuminated moon in the sky from anywhere in the world. However, it looks opposite in opposite hemispheres.
The right half of the moon is visible in the Northern Hemisphere, and the left half of the moon is visible in the Southern Hemisphere.
Lunar X and Lunar V on a first quarter moon
Lunar X and Lunar V are visible along the terminator—the line that divides light and dark—of a first quarter moon.
They are transient optical features that appear only for a few hours around the first quarter moon and can be seen through binoculars or a telescope.
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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