What is the rare blue supermoon and where can you see it tonight?
Words by ITV News Producer Hannah Ward-Glenton
Tonight the first supermoon of the year will be visible in the sky, providing a rare chance to see the moon looking bigger and brighter than usual. It is also a blue moon - although Sunday night's moon appeared red.
The combination of a supermoon and a blue moon is rare and tends to occur every 10 years on average.
What is a blue supermoon, how can you see it, and why is this blue moon red?
What is a blue supermoon?
A supermoon occurs when a full lunar phase syncs up with a particularly close orbit around Earth.
The moon will be 224,917 miles (361,970 kilometers) away - that's around 14 miles (23 kilometres) closer than the average distance of 238,855 miles (384,400 kilometres) away.
A blue moon is the term used to describe seeing the full moon twice in one month. The moon's full cycle lasts 29.5 days - marginally shorter than a full month - and that gap eventually results in a second full moon in a one-month period.
When can you see the blue supermoon?
The blue supermoon should be visible on Monday, Tuesday and Wednesday nights.
The sun will set at 8:14pm on Monday night, so the moon should be visible after that.
Weather conditions do affect visibility, but if it is a clear, cloudless night the moon should be easy to see across the UK.
Areas with less light pollution also have a better chance of getting a good view of the blue supermoon.
How rare is a blue supermoon?
A supermoon is usually visible three or four times a year thanks to the moon's constantly shifting, oval-shaped orbit.
About 25% of all full moons are supermoons, but only 3% of full moons are blue moons, according to NASA.
That makes the combination of a supermoon and a blue moon rare - a blue supermoon tends to occur every 10 years on average.
The next blue supermoons will occur in a pair - the first in January 2037, followed by one in March 2037.
What does a blue supermoon look like?
A supermoon should appear bigger and around 30% brighter than your average moon because of its proximity to Earth.
Sadly the moon will not actually be blue in colour, that's just the term used for the second appearance of a full moon in one month.
But experts say that not everybody will notice the difference.
“Unless you have looked at a lot of full moons or compare them in images, it is hard to notice the difference, but people should try,” Noah Petro, project scientist for NASA's Lunar Reconnaissance Orbiter said.
Is this why the moon has appeared red?
The blue supermoon has nothing to do with the reddish appearance of the moon in recent nights.
The change in colour of our regular moon is to do with weather conditions in North America, as ITV Weather Presenter and Meteorologist Chris Page explains.
"Canadian wildfire smoke has been dragged across the Atlantic in the upper atmosphere by the jetstream which has led to some amazing atmospheric optics," he said.
"[Sunday] night some saw very impressive sunsets and similar sunrises this morning. Deep red hues and milky skies were all thanks to the scattering of the shorter wavelengths of light, the blues, indigoes and violets. This left the red and orange hues of the light spectrum producing the very picturesque sunrise and sunsets."
"It also made the moon last night have a red hue to it too at moonrise and moonset," he added.
This is not uncommon during the summer months and sometimes can lead to reports of smoke being smelled from inside aircraft travelling across the Atlantic within the wildfire smoke plume.
When can we expect to see more supermoons?
The next supermoon is set to make an appearance on September 17, when the moon will be nearly 3,000 miles (4,484 kilometers) closer than the August supermoon. That night will also see a partial lunar eclipse, which should be visible across Europe, Africa and North and South America.
The October supermoon will be the closest, when it orbits Earth from 222,055 miles (357,364 kilometers) away.
The fourth and final of this year's supermoons will happen in November, at a distance of 224,853 miles (361,867 kilometers) from Earth.
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