Editor's note: To find out more about the rare supermoon lunar eclipse of Sept. 27-28 and how to see it, visit: Supermoon Lunar Eclipse 2015: Full 'Blood Moon' Coverage. Such an event won't happen again until 2033.
A supermoon is a spectacular sight in which the full moon of a given month occurs at the same time the moon is at perigee – the point in its orbit that brings it closest to Earth. During these events, the moon can appear up to 30 percent brighter and 14 percent bigger to skywatchers on Earth. See how the supermoon, or "perigee moon," works in the SPACE.com infographic.