The second full moon of May — a blue moon — will make an appearance this weekend.

A second full moon in a calendar month will occur on May 31 and be best seen at moonrise on May 30. Why is the Blue Moon one of astronomy’s most misunderstood terms?

See the best images of the Blue Moon from around the world as a second dramatic moonrise occurred in the same month in a rare sky event.

Do they really happen "once in a Blue Moon?” ...

Add Yahoo as a preferred source to see more of our stories on Google. This only happens once in a blue moon, literally. May's second full moon is almost here, and not only is it a rare blue moon, but ...

You’ve seen the silver orb, you’ve witnessed the blood moon, and you’ve even been stunned by the orange hue in it. Now, get ready for one of the sky’s headline acts this weekend — a rare “Blue Moon” ...

What is it about the Blue Moon that inspires us to write songs and name beers after it?

This only happens once in a blue moon, literally. May's second full moon is almost here, and not only is it a rare blue moon, but it will also be a micromoon. The blue moon will take place soon, ...