The year's biggest, brightest supermoon is set to grace Oregon skies this Sunday.

A supermoon, of course, is no bigger than the moon at any given time, but the term refers to when a new or full moon coincides with the lunar orbit coming in close proximity to Earth, according to National Geographic. The effect makes the celestial body appear larger and brighter.

The moon's orbit around the Earth is not a perfect circle, meaning the distance between the two bodies grows and shrinks as the lunar planet plods eternal laps around us.

And Sunday's supermoon marks the closest the lunar orb will come to our planet this year, just under 222,500 miles away. On Sunday night, the moon should appear about 7 percent larger and 16 percent brighter than usual, though astronomers caution it can be hard to notice the difference with the naked eye.

Skywatching in Oregon can be a risky proposition, too, especially in December. But forecasters are calling for a weak front to push out of the region on Saturday evening, so there may in fact be clear skies.

Though it will technically be the fourth supermoon of the year, none of the other three were visible as they came in the new moon phase, when the face of the moon shows black.

The best time to view the supermoon is right after sunset when the so-called "moon illusion" makes the already super-sized moon appear even bigger. The moon should sit near the constellation Taurus, though it shouldn't be hard to spot.

If the skies do end up under cloud cover, or you just don't feel like getting off the couch, the folks at the Virtual Telescope Project will be livestreaming the event.

If you miss it, not to worry. There will be another supermoon on Jan. 2, 2018.

-- Kale Williams

kwilliams@oregonian.com

503-294-4048