If there are a few things that you usually do "once in a blue moon," well you might want to get to it tonight.

Today's full moon officially set at 9:58 a.m., however while the sun is up, the moon faces the opposite side of the earth. That meant the full moon was not visible for most people in the Western Hemisphere but the moon will still look plenty full tonight.

The term "blue moon," has nothing to do with its color, and everything to do with the frequency of a full moon in a season.

According to Sky and Telescope magazine the phrase blue moon refers to the second full moon in a month that contains two full moons, at least that is how they misinterpreted the definition.

It wasn't until the 1980s, when the creators of a board game Trivial Pursuit gave the wrong definition popularity.

However, the term "blue moon," actually means the fourth full moon in a season, each season usually has three full moons. The year is divided into four equal seasons, each 91 or 92 days long. Since there are 29.5 days between full moons, four full moons occasionally get squeezed into one season.

According to Anthony Cook, astronomical observer at Griffith Observatory, there are two opportunities to spot the full moon. The first was between 6:30 a.m. and 7 a.m. PDT (9:30 a.m. and 10 a.m. EDT), however don't fret the second opportunity will be tonight at 7:13 p.m. PDT (10:13 p.m. EDT).

The last time a blue moon occurred was December 2009. If you miss today's opportunity to catch the "blue moon," your next chance will be July 31, 2015.

Usually, blue moons occur every 2.7 years, and although there is no observed difference from other full moons, this particular blue moon can serve as a fitting tribute to the first man on the moon, Neil Armstrong.