Once in a Blue Moon


Image credit: NASA/MSFC

On Aug. 31, if the night sky is clear, you will be able to see the second full moon of the month, which is called a “blue moon.”

You may have heard the expression, “once in a blue moon,” meaning “almost never,” because having 13 full moons in a calendar year — instead of the usual 12 — is rare.

Once in a blue moon, an individual who embodies the spirit of an explorer crosses the horizon in our culture. Such was Neil Armstrong. It is appropriate that the farewell to Armstrong coincides with the appearance of a blue moon.

A blue moon occurs just seven times every 19 years. The next blue moon will be on July 31, 2015.

Usually months have only one full moon, but occasionally a second one sneaks in. Full moons are separated by 29 days, while most months are 30 or 31 days long; so it is possible to fit two full moons in a single month. This happens, on average, every two and a half years.

So, as we say Godspeed to Mr. Armstrong, take a moment tonight to observe the blue moon, and give it a wink in honor of the first human to set foot on the surface of the moon.



Perseid Peak Performance

The All Sky camera network captured over 183 multi-station Perseid meteors Saturday night. Some truly spectacular events — see images below.

┬áThe Perseids have been observed for at least 2,000 years and are associated with the comet Swift-Tuttle, which orbits the sun once every 133 years. Each year in August, the Earth passes through a cloud of the comet’s debris. These bits of ice and dust — most over 1,000 years old — burn up in the Earth’s atmosphere to create one of the best meteor showers of the year.