Once in a Blue Moon happens tonight

     Yesterday's 97% full moon as seen from Ocean Grove by Blur Revision Media Design.

    Yesterday's 97% full moon as seen from Ocean Grove by Blur Revision Media Design.

    Take a walk out on the deck — or better yet, stroll along the shoreline — and enjoy the Blue Moon.

    Sure, you can drink a Blue Moon as well, but we’re not talking about beer.

    It’s the bright circle in the sky, and it’s a bit of an oddity. 

    Tonight’s moon does not mesh with the most popular definition of a Blue Moon, i.e. “the second of two full moons to occur in the same calendar month,” nor will it appear blue, because that only occurs with “exceedingly rare atmospheric conditions,” according to a report on EarthSky.org. 

    From the report:

    Rather, the August 2013 full moon will present the third of four full moons to fall in the same season. A season is defined as the period of time in between a solstice and an equinox – or vice versa. This full moon is the third of four full moons to take place in between the June 2013 solstice and the September 2013 equinox. That makes the August 2013 full moon a Blue Moon!

    seasonal Blue Moon, it doesn’t happen annually, and has many different names, such as the Full Sturgeon Moon, the Green Corn Moon, the Grain Moon, and the Full Red Moon. 

    If you’re a stickler for precision, the moon turns full on August 21 at 1:45 a.m. Universal Time, which translates to 9:45 p.m. today for us.

    “Astronomically speaking, the moon is full when it’s most directly opposite the sun for the month,” the EarthSky report explains. 

    The weather will cooperate, with a mostly clear sky and temperatures in the upper 60s, so enjoy your Blue Moon.

    Want a digest of WHYY’s programs, events & stories? Sign up for our weekly newsletter.

    It will take 126,000 members this year for great news and programs to thrive. Help us get to 100% of the goal.