A perigee moon, known as a supermoon, will take place on Sunday night, with a preview of the full moon beginning Saturday night. The moon will appear both brighter and larger than a normal full moon because of its location in the lunar orbit.
A supermoon occurs when the moon, the earth, and the sun are in alignment near the lunar perigee - the point in the moon's orbit that is closest to the earth. A full perigee moon reflects the sun's light and will appear 30% brighter than usual in the sky.
There will have been three supermoons during the summer season, and this weekend's moon will appear to be the largest until August of 2014. The best time to see the supermoon is when it is on the horizon. It can be viewed starting Saturday night and will end on Sunday, when it will reach its closest point to earth. The next perigee moon will occur on July 22.