AN INCREDIBLY rare celestial display is set to be visible tonight, where seven planets will align in an arc across the sky.

Mars, Jupiter, Uranus, Venus, Neptune, Saturn and Mercury will align in the same portion of sky for the last time until 2040.

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Alignments of four or five planets are not uncommon.

All it requires is their orbits bringing them to the same side of the Sun as the Earth.

But it’s remarkably rare for six planets to align, and even rarer for seven.

Only five planets, Mars, Jupiter, Saturn, Venus and Mercury, will be visible to the naked eye.

They will look like large, twinkling stars.

Jupiter, Saturn and Venus will appear as bright-white points of light.

Venus will be the brightest in the sky, shining twice as bright as the North Star, Polaris.

While Mars will have a distinct orange glow.

Uranus and Neptune are simply too far away from Earth, and therefore require a telescope or binoculars to view them.

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How to view ‘planet parade’

Stargazers will have to wait 15 years for the next alignment involving seven planets.

So it’s best to be armed with the right tips so you don’t miss out.

You should head outside at around 6pm for the best view.

The moment of alignment will be short, lasting until roughly 6:30pm GMT / EST in the UK and the US.

This is around the time Jupiter will fall below the horizon.

Mercury’s placement will also be low on the horizon, meaning it will dip out of visibility at about 7pm GMT / EST.

Find a piece of open sky, away from rooftops or a treeline.

Look to the east to find Mars with its reddish hue.

Jupiter and Uranus will be visible in the southeast.

Then turn your head to the west to spot Venus, Neptune and Saturn.

While binoculars or telescopes can give a detailed view of the planets, they can also limit the portion of the sky you can see.

What causes the alignment?

Planets are constantly moving, which means their paths occasionally cross into an alignment in Earth’s sky.

Dr Dan Brown, an astronomy expert here at Nottingham Trent University, explained to The Sun: “All planets including Earth move in more or less the same plane in our solar system. 

“So that from our perspective the planets are always very close to the apparent path of the Sun in the sky also known as the ecliptic.

“This means they will always be along this line.

“You could compare it with cars on a straight road.

“Since they can only drive on the road they will always be found along the road in more or less a line.

“What varies is how close they are to each other and when we can see them.”