Long Island sky watchers can look forward to this month’s full “supermoon,” on the 14th, which won’t be just any old supermoon.

It could actually be considered “an extra-super moon,” according to NASA.

A moon appears to be supersized when a full moon passes closer to Earth as it moves along its elliptical-shaped orbit. This year is going out with a string of three supermoons — with November’s sandwiched in between one on Oct. 16 and one on Dec. 14.

According to EarthSky.org, which offers daily updates on the night sky, November’s full moon will pass a neighborly 221,524 miles from earth.

It “is not only the closest full moon of 2016 but also the closest full moon to date in the 21st century,” according to NASA’s website. The full moon won’t come this close to Earth again until Nov. 25, 2034, NASA said.

So, how will it appear, seen up close and personal, relatively speaking?

advertisement | advertise on newsday

“Because the moon is about 5.5 percent closer than normal, it will appear about 5.5 percent larger than normal,” said Frederick Walter, professor in Stony Brook University’s physics and astronomy department. That means it will appear 11 percent larger than a full moon that’s at its farthest distance away.

November’s supermoon will also be about 11 percent brighter than normal, he said.

Walter advised taking a look at moonrise or moonset, since the moon “always looks larger when on the horizon.”

It’s “a well-known optical illusion caused by the availability of reference objects on the horizon.”

Even though the phenomenon is gathering a lot of attention on social media, sky watchers may still want to mark their calendars.

“Unless you are told in advance, you would probably not notice that it is bigger and brighter than normal,” Walter said.