First things first: a blue moon is not blue. At least it doesn’t HAVE to be, and without some post-processing help most of the pictures of yesterday’s moon would probably have shown the same gray, white, yellow, or orange orb we’re all used to seeing.

A “blue moon” is simply a second full moon happening in the same month, and yesterday’s full moon was the second of July: hence, a blue moon.

The reason we have the saying “once in a blue moon” in English is that this event is actually quite rare. The last one was in 2012… the next won’t be till 2018. And so, in celebration of this rare celestial event, we thought we’d collect the best photos of “Blue Moon 2015” from the 500px community and share them with you.

There are some truly stunning shots in here, so be sure to scroll down to the very end!

Blue Moon rising behind New York City by Anthony Quintano on 500px.com

Blue Moon Over New York by John Amelia on 500px.com

Blue Moon by Linda Enfield on 500px.com

Apocalyptic Blue Moon by ??  ? on 500px.com

Blue Moon on Approach by bbentleyphoto  on 500px.com

Blue Moon by Rui Velindro on 500px.com

Blue Moon Rising by Arthur Okoun on 500px.com

Blue Moon Over Downtown Dallas by Michael Zheng on 500px.com

The Blue Moon Boston by Manjunath Chandrashekar on 500px.com

Blue Moon by Giuseppe Rizza on 500px.com

Trevone Bay - Blue Moon by Alex Stevenson on 500px.com

Blue Moon by Nate Zeman | natezeman.com on 500px.com

Blue Moon by Emanuel  Love on 500px.com

Once in a blue moon by Dan Martland on 500px.com

"Blue Moon" by Amanda Stup on 500px.com

At the quay by Krzysztof Zegzula on 500px.com

Blue moon and Jet by MASA KASUYA on 500px.com

Once in a blue moon by Mikhail Bogatchev on 500px.com

The Blue Moon Shines Bright by Genzo Toride on 500px.com

Moon over Manhattan by Craig Howe on 500px.com

Blue Moon by masahito ookawa on 500px.com

If you’ve got your own Blue Moon photo from last night (whether or not it’s actually blue) upload it to your 500px account and drop a link in the comments! Bonus points if you’ve got a cool story to go with the photo.