SKYWATCHERS were treated to a fantastic show last night when the sky was 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.

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 about seven per cent bigger than average because it is closer to Earth.