On 14 November, a rare astronomical event will take place – a mega supermoon. But what does that mean? Here's everything you need to know.

What is a supermoon?

Supermoon is not a technical term. Its real name is perigee full moon. Because the moon's orbit is elliptical, the point at which it is closest to Earth – known as perigee – is 30,000 miles closer than when it is at its furthest point – apogee. When a full moon closely aligns with perigee, we call it a supermoon.

What is a mega supermoon?

Again, not a technical term. Normally, a supermoon takes place when perigee aligns with the full moon within a day. However, the 14 November full moon will align with perigee within just two hours. Such a close timeframe has not been witnessed since 1948 and it won't happen again until 25 November, 2034.

What will it look like?

Supermoons can appear as much as 14% bigger and 30% brighter than a full moon that appears during apogee. So the mega supermoon will appear larger and brighter than normal. Cloud cover will obscure the view, however, so a clear night will be required to see it.

November's full moon is also called a Beaver Moon. Why?

The full moon in November is also known as a Beaver Moon because it was named so by Algonquin tribes that lived in northern Michigan and Canada. Apparently it was the time when they set beaver traps before the swamps froze to make sure they had furs for winter. It is also sometimes called a Frost Moon.

Will it cause a change to the tides?

Yes. Every full moon results in larger tides than usual and perigee full moons bring the highest. So mega supermoon will result in unusually high tides. There should not be so much of an affect to cause any flooding though.

Exactly what time can you see the mega supermoon?

Unfortunately for the UK, the full moon reaches its closest point to Earth at 13.42 GMT on 14 November. However, there will be a live broadcast of the event beginning at 00:00 which you can watch here.

When is the next supermoon?

There will be another supermoon on 14 December. Unfortunately this full moon is somewhat unwelcome, as it coincides with the Geminid meteor shower - the brightness of the moon will reduce the visibility of the meteors.

News photos of the year 2015
27 September 2015: The supermoon rises behind Glastonbury Tor. This supermoon, so called because it was the closest full moon to the Earth this year, was particularly rare as it coincided with a lunar eclipse, a combination that had not happened since 1982 and won't happen again until 2033 Matt Cardy/Getty Images