View at EarthSky Community Photos. | Lorraine Boyd captured this from New York on November 9, 2024, and wrote: “Peeking through tree limbs at the first quarter moon (50% illumination), just after sunset.” Thank you, Lorraine.
First quarter moon
Here are the characteristics of a first quarter moon:
– It’s the moon phase halfway between new moon and full moon.
– As viewed from anywhere on Earth, a first quarter moon appears at its highest in the sky at sunset. It rises around noon and sets around midnight.
– It’s called a quarter moon, but, from Earth, it looks half-illuminated, like half a pie. Or you might say that – at first quarter moon – we’re seeing half the moon’s day side or a quarter of the whole moon.
As seen from the north side of the moon’s orbital plane, the terminators (lines between sunny and shadowed sides) of the Earth and moon align at first quarter moon, and only the near half of the moon’s day side is visible from Earth. Image via Wikipedia Commons. Click here to see the animation.View at EarthSky Community Photos. | Mohamed Mohamed of Tripoli, Libya, captured this great image of the first quarter moon on January 28, 2023. Thank you, Mohamed!
Quarter moon? Half moon?
There’s another reason we call this moon a quarter and not a half. It’s because it’s one quarter of the way around in its orbit of Earth, as measured from one new moon to the next.
Do you have access to a small telescope? Here are some telescopic sights to see on a first quarter moon:
Tom Wildoner in Weatherly, PA, captured this photo of Rupes Recta. He wrote: “Rupes Recta, a linear fault line, or rille, appears as a straight shadow during the first quarter phase of the moon giving it the nickname the Straight Wall. This fault has a length of about 68 miles (110 kilometers). The small (11 miles wide) crater Birt lies just to the west.” Thank you, Tom! Used with permission.View at EarthSky Community Photos. Frank Lu of Texas captured this image on February 5, 2025, and wrote: “Inspired by Deborah Byrd’s article in EarthSky’s Astronomy Essentials on Lunar V and Lunar X, I went out looking for the Lunar X and Lunar V on this 1st-quarter. I’m extremely pleased to find them.” Thank you, Frank!
More articles about moon phases
As the moon orbits Earth, it changes phase in an orderly way. Follow the links below to understand the phases of the moon.
Bottom line: The first quarter moon occurs halfway between new moon and full moon. One quarter of the moon is visible from Earth, meaning that you see half of the daylit side of the moon, looking like half a pie.
Our Editor-in-Chief Deborah Byrd works to keep all the astronomy balls in the air between EarthSky's website, YouTube page and social media platforms. She's the primary editor of our popular daily newsletter and a frequent host of EarthSky livestreams. Deborah created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Prior to that, she had worked for the University of Texas McDonald Observatory since 1976, and created and produced their Star Date radio series. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. In 2020, she won the Education Prize from the American Astronomical Society, the largest organization of professional astronomers in North America. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.
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