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

Today 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.

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".

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

The moon will appear about seven per cent larger and 15 per cent brighter, although the difference is barely noticeable to the human eye.

The exact moment of the full moon will be at 15:47 GMT.