Rare Blue Moon Visible Over Armonk Skies

WESTCHESTER COUNTY, N.Y. -- Westchester residents were treated to a blue moon in the night sky on Friday.

A look at the blue moon visible Friday night in the area.
Photo Credit: *Skip Pearlman*

The blue moon next to the dome of the U.S. Capitol on Friday.
Photo Credit: *NASA/Bill Ingalls*

08/01/2015 12:30 p.m.

The modern definition of a blue moon is the second full moon in a calendar month, according to NASA. Most blue moons appear gray as normal. The phrase "blue moon" is not connected to a change in color.

Since the moon completes a full cycle approximately every 29.5 days, getting two full moons in a single month is somewhat rare.

The next blue moon -- by the modern definition -- won't take place until Jan. 31, 2018.

The rare frequency of their occurrences led to the origination of the phrase, "Once in a blue moon."

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