— -- There's a reason why "once in a blue moon" is a saying and Friday night proved it.
Here are some of the best Blue Moon photos from Friday night, from Washington D.C. to Seattle:
Don't let the name fool you, though. Blue moons are very rarely blue. Most are pale gray and white, resembling a moon on any other night.
A truly blue colored moon can occur on rare occasions, according to NASA, with most being spotted after volcanic eruptions.