Skywatchers are in for a treat this week when the moon is set to put on one of its finest shows.

On Sunday, December 3, the sky will be illuminated by a so-called supermoon.

The phenomenon happens when a full moon or new moon coincides with the moon's closest approach to the Earth.

Its orbit around Earth is not a perfect circle; it is elliptical (oval shaped).

That means the distance between the moon and the Earth varies.

FROM 2014: 14 super supermoon pictures: Your images of spectacle in the sky

The point on the orbit closest to Earth is called the perigee and the farthest is the apogee. On average the distance it is about 238,000 miles.

Astrologer Richard Nolle first coined the term supermoon in 1979.

He said it was "a new or a full moon that happens when the moon is at or near its closest approach to Earth in its orbit".

FROM 2015: Your pictures of the blood red 'supermoon' that was seen for the first time in 30 years

A super full moon looks about seven per cent bigger than average because it is closer to Earth.

Let's hope for clear skies and a good show on Sunday!