Mars will be closer to Earth tonight than at any point in the past 17 years.

The Red Planet will be the second brightest object in the night sky after the Moon, astronomers say.

The planet is at its point of opposition, with the Earth passing directly between it and the Sun and will appear "effectively as a full Mars", according to NASA.

It will be visible with the naked eye and appear slightly reddish in colour.

From the UK the planet will rise above the horizon at about 7pm but will be best viewed after midnight - ideally in an area with a clear sky and minimal light pollution. 

The Argus: It will be visible with the naked eye and appear slightly reddish in colour It will be visible with the naked eye and appear slightly reddish in colour

To view Mars in the night sky you should look to the right of the Moon and towards the constellation Pisces. 

"Simply go outside and look up and, depending on your local weather and lighting conditions, you should be able to see Mars," NASA wrote in a blog post. 

Mars reaches its closest point to Earth every two years, but not every close approach is equal, with distances varying by millions of miles even during the closest points. 

The two planets aren't on an exactly circular orbit - so every 15 or 17 years the gap gets a little bit closer - this year Mars will come 38.6 million miles from Earth. 

This is the closest approach since 2003 when Mars was 34 million miles away - the closest in 60,000 years. It won't be that close again until 2287. 

The next time Mars and the Earth will be as close as it is this year will be in 2035 - around the time NASA hopes to send astronauts to the Red Planet.

"'If Earth and Mars had perfectly circular orbits, their minimum distance would always be the same. However, they have elliptical (egg-shaped) paths," NASA said.

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"In addition, gravitational tugging by planets constantly changes the shape of their orbits a little bit. Giant Jupiter especially influences the orbit of Mars.

"The orbits of Mars and Earth are also slightly tilted with respect to each other."

This is why the distances can vary between the two planets by millions of miles.

"When Mars and Earth are close to each other, Mars appears very bright in our sky. It also makes it easier to see with telescopes or the naked eye," NASA wrote.

"The Red Planet comes close enough for exceptional viewing only once or twice every 15 or 17 years and the next close approach is in 2035."

When Mars rises in the sky tonight, EarthSky reports that it will appear like a "resplendent red star in the east every evening and in the west before dawn".