How to see the 'blue supermoon' in the UK tonight

London, UK. 18th August 2024. UK Weather: Sturgeon Blue Supermoon (Waxing Gibbous) at 99% sees a passenger jet cross the lunar surface seen from north-west London on 21:11 Sunday evening. Traditionally called the Sturgeon Moon because the giant sturgeon of the Great Lakes and Lake Champlain were most readily caught during this part of summer,” according to the Old Farmer's Almanac. Credit: Guy Corbishley/Alamy Live News
A passenger jet seen crossing the blue supermoon on Monday night from London (Guy Corbishley/Alamy Live News)

Photographers captured a rare event over Britain’s skies this week - a ‘blue supermoon’ - and there’s still a chance to see it again tonight.

The so-called blue supermoon, which appears bigger in the skies due to the moon’s orbit, appeared a rusty red over Britain due to smoke in the atmosphere from wildfires in North America (despite the name, blue moons are not actually blue).

The smoke particles mean that light is scattered in such a way as it passes through the atmosphere that the reddish hue is more visible than usual.

The full moon actually peaked yesterday evening in the UK, but sky-watchers may be able to get a better glimpse tonight due to clearer skies, with the moon still appearing full from Sunday morning through early Wednesday morning, according to NASA.

This month’s full moon is also known as the Red, Corn, Barley or Dog Moon - and as the ‘Sturgeon’ moon, a Native American term due to the fish being able to be caught in the Great Lakes in summer.

Supermoons are when the moon is closest in its orbit to the Earth, making it appear bigger and brighter than usual.

Supermoons (or perigean full moons, to be technical) can be up to 14% bigger and 30% brighter than normal full moons – and happen when a full moon coincides with the moment the moon is closest to Earth on its (slightly wonky) orbit.

Cambridge, UK. 19th, August, 2024. The blue supermoon comes into view as the clouds drift apart. A blue supermoon is a rare lunar phenomenon where a blue moon, which is the third full moon in an astronomical season, and a supermoon, which occurs when a full moon is at its closes approach to Earth, coincide. Credit: David Tramontan / Alamy Live News
The blue supermoon seen from Cambridge this week (David Tramontan / Alamy Live News)

The term ‘supermoon’ was coined in 1979, with NASA saying: "When a full moon appears at perigee [its closest point to Earth] it is slightly brighter and larger than a regular full moon - and that's where we get a “supermoon”.’

The moon has an elliptical orbit around the Earth, and supermoons happen when full moons coincide with the time the moon is closest to Earth.

Confusingly, there are multiple definitions of a blue moon - one being when there are two blue moons within a calendar month.

These are known as 'monthly' supermoons.

But another definition is the third full moon in an astronomical season (between equinoxes and solstices).

This August’s blue supermoon is one of these ‘seasonal’ blue moons.

The term ‘blue supermoon’ is used when a full blue moon coincides with a supermoon - this is quite rare, as just 6% of full moons are blue moons and 25% are supermoons.

NASA says: "It’s a full moon, a supermoon, and finally a blue moon. You may hear it referred to as a super blue moon or blue supermoon as a result.’

NASA says that the moon will appear full for three full days, from Sunday through until Wednesday morning.

Technically, the moon reached its peak on Monday August 19, 2024, at 2:26 PM EDT (7.26PM British time).

When the moon is at its closest to Earth, it can appear around 14% bigger, but NASA says that in practice, you may not notice.

When the moon is at its ‘perigee’, its closest point to Earth, it is at an average distance of around 226,000 miles - while at its ‘apogee’, its furthest point, it’s about 253,000 miles away.

If you miss this blue supermoon, you’re in for a bit of a wait - the next ‘seasonal’ blue supermoon isn’t until 21 August, 2032.

The next ‘monthly’ blue supermoon will be in January 2037, followed quickly by one in March 2037.

NASA says: “The time between super blue moons is quite irregular ― it can be as much as 20 years ― but in general, 10 years is the average.”

The next 'supermoons' are on 18 September, 17 October and 15 November.