- A Supermoon occurs about once a year
- It is much larger and brighter than an average full moon
- It happens when the moon is full and the moon is at its closest point to earth
- The moon will set over some of the U.S. before reaching its closest point
The heavens will deliver a rare treat to moonstruck romantics and werewolves Sunday who rise before the sun.
A feat of lunar synchronicity will create a Supermoon.
This happens when the moon is full and at the same time reaches its perigee -- the closest point to Earth in its orbit, according to NASA.
It makes for the biggest, brightest moon of the year. A Supermoon, sometimes called a Super Full Moon, is 14% larger and 30% brighter than most full moons, NASA says.
Taken separately, neither a full moon nor the perigee is a big deal. The moon is full roughly once a month, and it reaches its perigee just as often, but the next time both will coincide will be August 2014.
This year's magic moment occurs at 7:32 a.m. ET, but it would be wise to wager a gander earlier.
In some parts of the United States the sun will rise beforehand, outshining the Supermoon's splendor. And the moon itself will dip below the horizon in parts of the country, just before it hits its perigee.
The West Coast should get a great view of the perfect moment, when the moon is only 221,824 miles from Earth.
There is nothing to fear from the moon being so close and bright, NASA says. It will have no more effect on tides or seismic activity than usual.
Two weeks later, the moon will swing out to the farthest point in its orbit around Earth, when it will be 252,581 miles away, NASA says.
Astronomers and swooners may have noticed the moon shining brightly early Saturday, when it put on a dress rehearsal. It was not quite full and not as close to the planet as it will be Sunday before dawn.