Celestial News & Events

The Moon Is "Blue" This Wednesday...Or Is It?

If skies are clear this Wednesday, you'll see the full Moon — but it's not the "true" Blue Moon.

Blue Moon

“True” Blue Moon Occurs Sunday, August 22nd

If skies are clear this weekend, we’ll see the full Moon. And not just any old full Moon, but the Blue Moon — the “true” Blue Moon.

Rising Moon

Celestial Objects to Observe

Where Does the Phrase "Once in a Blue Moon" Come From?

We'll see a "blue Moon" next Friday, but what does that mean? From the Middle Ages to the game of Trivial Pursuit, a folklorist explores the origin of the phrase.

Rising full Moon


What Is A Blue Moon in Astronomy?

Is Friday's full Moon "blue"? Depends on who you ask, but if someone answers yes, it's because of a mistake in a 1946 issue of Sky & Telescope.

Astronomy Questions & Answers

When's the next blue Moon?

When's the next blue Moon? To read the full story with a schedule that shows all blue Moons through 2020, see our article "What is a Blue Moon?" Here's the abbreviated version: In 1999 Sky & Telescope admitted to its “blue Moon blooper,” an error that had crept onto the…