LONDON: Five planets will be visible in the night sky this week in a rare astronomical alignment which has not happened for more than a decade. Mercury, Venus, Mars, Jupiter and Saturn will all appear together for the first time since 2005.

The alignment was to be visible in Britain just before dawn from January 20 (Wednesday), but astronomers say the best view is likely to be on the morning of February 5. The planets will from a diagonal line from the Moon to the horizon and with clear skies and good eye-sight, should be visible with the naked eye, reported daily The Telegraph.

Dr Robert Massey of the Royal Astronomical Society said spotting Mercury would be a challenge as it would be close to the horizon, but the other planets should be easy to see in before dawn.

“There will be a dance of the planets, and now is the time to get out and have a look,” said Dr Massey. “It will be well worth getting up for.

“People will struggle to see Mercury, it will probably just look like a star but if we get good weather we should be able to see Venus, Saturn, Mars and Jupiter well. But people should have a shot at seeing them altogether.

“Venus will be very obvious in the south east and Saturn will be a little bit higher up to the right. Further over at due south, you’ll see Mars and way beyond in the south east will be Jupiter.

"They won't be in an exact straight line, because you virtually never get that in astronomy. They will be more scattered."

Jupiter and Venus will appear side by side over the next two nights, according to astronomers.

The planets rarely come together because of their differing orbits.

Mercury will appear just three degrees above the horizon – the equivalent of three thumb widths with an outstretched arm - so will be the trickiest planet to spot.

The best time to see the alignment is around 6.45am in the morning, just before dawn. It is best to try and see Venus and then look for the rest of the planets.

Four of the five have already been visible in the early morning sky in recent weeks, but Mercury was to join them for the first time on Wednesday.

Dr Massey added: “If you have binoculars you will be able to see Jupiter’s moons and the red tinge of Mars. You probably won’t be able to see Saturn’s rings but it will have a funny shape because of the rings which you should be able to pick out.

“If you are using binoculars it’s important not to look towards the sun when it rises.”

The stars Antares and Spica will also be visible in the same patch of sky. Uranus and Neptune are the only two planets that will not be on show.

And if you fail to catch the alignment this month, it will be happen again in August of this year although the late days of summer are likely to make it even more difficult to see in Britain. After that, the five planets will not be seen together again until October 2018.

People hoping to catch a glimpse of the alignment should choose an open spot, away from tall buildings and city lights to avoid light pollution.