The brightest and largest supermoon of this year is set to grace our skies this weekend, on Sunday, August 10. Skywatchers are thereby in for a celestial treat!
The term 'supermoon' refers to a full moon that coincides with our moon's closest approach in its monthly orbit to Earth. Just as planetary orbits around the sun are elliptical, so, too, is the orbit of our moon. This results in points of apogee and perigee -- with apogee being the furthest point of orbit from Earth at approximately 252,000 miles, whereas perigee is the closest approach at approximately 222,000 miles.
When our moon's perigee coincides with a full moon, our moon looks larger than normal, hence the now popular use of the term 'supermoon.' The full moon that occurred on July 12 last month, for example, was the first supermoon of the year. And, while this Sunday's supermoon is the year's second, it nonetheless shall be the brightest and largest of the entire year! Astronomers estimate the moon to appear 16% larger and 30% brighter.
Why is that? The reason centers around the moon reaching the crest of its fullest phase -- which EarthSky.org has reported to be around 11:09 AM Pacific Time -- within the same hour that the moon approaches its point of perigee.
However, for photo hounds to achieve the illusion when the moon appears larger near the horizon from the Ponzo illusion effect, it should be noted that Sunday's moonrise will occur at 7:34 PM. The timespan immediately following moonrise is recommended for folks to get their photos of the supermoon.
Should you miss this Sunday's supermoon, don't fret, because this year 2014 has been blessed with a trio of summer supermoons. The third and final supermoon of the season shall take place on September 9 -- albeit not as large as the one set to occur this Sunday, August 10.
As for factoid buffs out there who love learning about the names of full moons, the Farmer's Almanac has cited August's full moon as the Full Sturgeon Moon. Full moon names derive from Native American tradition, as tribes kept track of the seasons. This month's full moon was named after the sturgeon fish, because by August's moonlight many tribes of the Great Lakes region could catch the large sturgeon fish swimming in abundance this time of year. Other names for August's full moon, according to the Farmer's Almanac, include the Grain Moon, the Full Red Moon, and the Green Corn Moon.
What's more, the annual Perseid meteor shower has already arrived, with its annual peak display taking place in the few days following the August 10 supermoon. While the supermoon's light might wash out the faintest of the Perseid 'shooting stars,' the brighter fireballs nevertheless might still be visible by the naked eye against the backdrop of the supermoon.
Perhaps a celestial spectacle involving both this Sunday's supermoon and the Perseid meteor shower could be in store for skywatchers this weekend. So, keep looking up!