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Rare blue moon to brighten night sky this Halloween

The so-called blue moon is seen above Washington on July 31, 2015. The blue moon is the second appearance of a full moon in the same calendar month. The next blue moon will not be seen until January 2018. AFP PHOTO/MANDEL NGAN (Photo credit should read MANDEL NGAN/AFP via Getty Images)

(WJW) — Eyes to the sky! There will be two full moons this October.

Normally, there is one full moon per month. But in 2020, October will have two full moons — one on Thursday, October 1 and then again on Halloween.


According to NASA, the rare phenomenon is called a blue moon.

Despite the name, the blue moon will not actually appear blue in color. In fact, a blue moon does not look any different than a regular, monthly full moon.

NASA says a blue moon usually only occurs every two-and-a-half years. The last blue moon appeared on March 31, 2018.

The term blue moon has been used to describe the second full moon in a calendar month since the 1940s. It inspired the phrase “once in a blue moon…”

In recent years people have been using the term “blue moon” to refer to another type of moon, EarthSky reports.

The term can also describe the third of four full moons in a single season — between a solstice and equinox. This is known as a seasonal blue moon.

The next seasonal Blue Moon will occur on August 22, 2021.