‘Supermoons’ have appeared in the media a few times this year. But what are they? And when will the next one occur?

The term ‘supermoon’ is a relatively new one for astronomers. It is a recent colloquialism used to describe the times when the Moon’s closest approach to Earth coincides with either a full or new Moon phase.

By one definition we can expect to see four to six supermoons in any one year. In 2014 we are experiencing five but don’t get to see them all. In January this year there were two supermoons that we didn’t really see. That’s because they occurred at a new Moon phase – the point when the Moon in its orbit is more or less directly between the Earth and the Sun – and therefore is pretty much invisible.

Much more exciting are the ones that occur at full Moon. There are the Super Full Moons, of which there are three this year, and we’re having a beauty in the early hours of Monday 11 August (NZ time).

If you can convince yourself to rise early (approximately 6.10am) look just south of west (more or less in the opposite direction of the early sunrise) and, cloud permitting, you’ll see a beautiful golden orb quickly setting, the biggest it will appear this year.

At that point the Moon will be coasting about 356,000 km’s away. Interestingly, a few hours prior it will have been a few thousand klicks closer, but because its phase is not exactly full until 6.10am we can’t call it ‘super’ until then.