Supermoon Saturday: What you need to know

One day before the 'supermoon,' a commercial airliner crosses the waxing gibbous moon on its final approach to Los Angeles Airport as viewed from Whittier, Calif., Friday, July 11, 2014. (AP Photo/Nick Ut)

What could be fuller than a full moon?

A full "supermoon."

The moon will be at the closest point in its orbit around the planet on Saturday night, meaning it will appear bigger and brighter in the sky than normal. The proximity coincides with its typical full lunar phase, meaning the moon will be at its absolute peak intensity. Scientists expect it will appear 14 per cent larger than usual.

The moon travels around Earth in an elliptical orbit, meaning it's sometimes closer, sometimes farther away. On Saturday, the moon will be 50,000 kilometres closer to the planet than it is at the farthest point in its orbit.

The moon rotates through its cycles every 28 days, so its being close and full at the same time is an added rarity.

Ocean tides, which are influenced by the moon's gravity, will be slightly higher as a result, but the moon will only appear slightly larger in the night sky.

Saturday's supermoon is the first of three this summer. The next supermoon will be even bigger and brighter when it appears on Aug. 10, and a third one will occur Sept. 9.

The phenomenon, which astronomers call a "perigee moon," is much more common than lunar eclipses. There were three supermoons last year, too.