Rare super moon to hover over California skies this week. It only happens once a decade

California night skies will be illuminated by a “Super Blue Moon” this week — something you’ll only get to see once in a decade.

According to Time and Date, an online calendar, the supermoon will make its ascent at roughly 6:05 p.m. Wednesday on the West Coast. Despite its name, the blue moon has nothing to do with the color, but everything to do with it’s rarity.

Here’s what we know about Wednesday’s astronomical event:

Best time to watch the moon

The full moon on Wednesday will be up all night long, said Kyle Watters, the director of the Sacramento State Planetarium, in an email to The Bee.

“The way that we get a full moon is by having the entire side of the moon facing (the Earth) being illuminated by the sun,” Watters said. “And this only happens when the moon and the sun are on opposite sides of the Earth, so that they rise and set at opposite times.”

Which means that any time on Wednesday night would be a good time to go outside and stare at the Super Blue Moon.

A bonus: “The planet Saturn, just a few days from its closest and brightest for the year, will appear near the Moon,” according to NASA.

How rare is a super blue moon?

Full moons are typically 20 to 30 days apart, Watters said. Having two in one month is what makes this one “blue.”

“It is pretty rare for there to be two full moons in the same month,” he said.

This typically happens every two to three years, according to NASA, which is due to the moon’s monthly cycle.

But, Wednesday’s full moon is also a super moon which only adds to the rarity of the event. During a super moon the Moon’s orbit is closest to Earth’s. According to NASA, this makes the moon slightly brighter and larger than average.

The combination of both a blue moon and a super moon together in one night only occurs every 10 years.

The next Super Blue Moon will be in January 2037. Then it won’t happen again until March 2037, according to NASA.

Every once in a blue moon

The term “once in a blue moon” is often used to express a rare occurrence. Is there any correlation between the expression and tomorrows moon?

Turns out there may be.

“I have been told that the phrase ‘once in a blue moon’ is actually older than the astronomy use of “blue moon” to mean the second full moon in a month,” Watters said.

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