What is a Harvest Moon? How to catch the last supermoon of 2023

Friday's full moon - the Harvest Moon - is set to be the last supermoon of 2023.

On September 29, the moon will be near its closest approach to the Earth and may look slightly larger and brighter than usual.

This happens when it reaches a spot in the sky completely opposite to the sun.

What is a supermoon?

Supermoons occur because the distance between the moon and the Earth changes over time.

The moon’s orbit around the Earth isn’t perfectly circular, it's shaped like an ellipse.

A supermoon occurs at perigee: the point in the moon's orbit where it is closest to Earth, and a perigee full moon appears a little brighter and larger than the average full moon.

The opposite is a "micromoon", when the moon is at its furthest from us.

Why is this week's full moon called a Harvest Moon?

This supermoon is a Harvest Moon because it is the closest full moon to the equinox.

The autumn equinox occurred at 7.50am on September 23.

How can I catch the supermoon?

The answer is simple: make sure to look up at the sky on September 29.

At this time of year, the sun will set in the west, so the full moon will rise near due east.

As it comes up, it may look orange or even red - especially if it's low on the horizon.

This is because the moon's light is filtered as it travels through more of the Earth's atmosphere than when it's overhead, and red light is scattered least by the atmosphere.

So, there is a way to make sure you get the best view - ensuring you have a low and clear horizon.

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