A first quarter moon shows half of its lighted hemisphere – half of its day side – to Earth.
First quarter moon comes on June 12, 2016 at 0810 UTC (3 a.m. CDT). Translate to your timezone.
We call this moon a quarter and not a half because it is one quarter of the way around in its orbit of Earth, as measured from one new moon to the next.
This moon appears half-lit to us, and half moon is a beloved name (although not an official one). Still, it’s good to recall that the illuminated portion of a first quarter moon truly is just a quarter. On the night of first quarter moon, we see half the moon’s day side, or a true quarter of the moon. Another lighted quarter of the moon shines just as brightly in the direction opposite Earth!
A first quarter moon rises at noon and is high overhead at sunset. It sets around midnight.
First quarter moon comes a week after new moon. Now, as seen from above, the moon in its orbit around Earth is at right angles to a line between the Earth and sun.
As the moon orbits Earth, it changes phase in an orderly way. Follow these links to understand the various phases of the moon.
Deborah Byrd created the EarthSky radio series in 1991 and EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. 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.