Skies in the Pacific Northwest have started to clear, which should bode well for stargazers hoping to catch the supermoons coming this season.
There will be several big moons in 2021, according to astronomers, most notably the full moons on April 26 and May 26, the latter of which will take place during a total lunar eclipse.
The term “supermoon” is unofficial, though it is generally thought of as a full moon that is a little larger and brighter than normal as it reaches its closest point to Earth. Because the moon follows an elliptical path around the Earth, its distance from our planet (known as the perigee) varies throughout the year.
Scientists refer to the phenomenon as “perigee syzygy,” meaning the alignment of the Earth, moon and sun at the moon’s closest point in its orbit.
The term “supermoon” was coined not by an astronomer but by astrologer Richard Nolle, who in a 1979 magazine article said he considered the moon to be “super” when it is within 90 percent of its closest approach to Earth in a given orbit. In 2000, Nolle published a chart listing every supermoon for the next 100 years, according to his calculations, posted online at astropro.com.
Over the years, different organizations have used different calculations to determine what, exactly, counts as a supermoon, with most landing on a perigee of 223,000 to 225,000 miles. That difference occasionally invites disagreement about how many supermoons there are in a given year.
Two of this year’s full moons are inarguably super. The April 26 full moon will come within 222,064 miles of Earth, and the May 26 full moon will be the closest of the year at 222,023 miles, according to timeanddate.com.
