What is a 'Supermoon?' August's Will Be The First Of Three In A Row

A trio of “supermoons” are on the lunar calendar. August’s supermoon sets off three in a row. (Photo by @repostapp via Flickr)

By MARC TORRENCE (Patch National Staff)

The first of three consecutive “Supermoons” rises Saturday, but lunar lovers in Metro Detroit may be out of luck.

The National Weather Service is predicting dreary weather for Saturday night, with mostly cloudy skies and a 40 percent chance of rain.

Oh, well. Perhaps the skies will cooperate in September and October.

What is a Supermoon?

Supermoon is the unofficial term for when the full moon cycle coincides with the moon’s closest approach to Earth during its oval-shaped orbit. The moon appears slightly larger than normal in the sky and can make for a spectacular view.

The technical term is full moon perigee. Perigee is when the moon is closest to the Earth, as opposed to apogee, which is when it’s the farthest.

The image below shows the relative sizes of the moon during both.

The term Supermoon was first used in 1979 by astronomer Richard Nolle, who defined it as a full moon that occurs within at least 90 percent of its closest orbit, according to space.com.

Sept. 28 and Oct. 27 will also fall under this definition, with September’s full moon being the largest of the three, as well as a total lunar eclipse, or “blood moon,”according to EarthSky.