Earthsky.org, 7/19/13
It’s a large waxing gibbous moon that lights up the evening sky on the night of July 19. The moon is moving toward full phase, to usher in the year’s third and final “super” full moon – another supermoon – on July 22, 2013.
Another supermoon coming up on July 22
The July 2013 full moon will be the second full moon after the June solstice. There are usually three full moons in between a solstice and an equinox, or vice versa. Seven times in 19 years, however, four full moons fall in a single season. In that case, the third of a season’s four full moons is sometimes called a Blue Moon. The next Blue Moon by this definition will happen next month, on August 21, 2013
