Orbit glossary
What is supermoon?
Supermoon is an informal name for a full or new Moon occurring near perigee, when the Moon appears somewhat larger than average.
What it means
Supermoon describes part of the Moon's motion or position in space. The Moon follows a slightly elliptical, tilted orbit, so its distance, apparent path, rise time, and alignment with the Sun change continuously. These orbital relationships explain many patterns that observers notice from night to night.
For a deeper look with practical observing advice, read the Moonrise Moment guide to supermoon.
Sources and further reading
This definition was written in plain language and checked against these science references.