A rare 'Christmas star', where the two largest planets in our solar system will align and appear visible for the first time in more than 800 years, is set to light up the sky.

Jupiter and Saturn will appear closer in the sky to each other than they have since the middle ages, appearing as a bright double point of light for the first time in centuries.

The phenomenon has been nicknamed the Christmas star, or the Star of Bethlehem, and will be visible on Monday, December 21, which is also the day of winter solstice.

The two planets will appear so close, approximately 0.1 degrees apart, that they will look like one bright object. The last time this was recorded was in 1623, more than 400 years ago, but many people discounted that year as they were very low in the sky and difficult to view.

Right now, and for the rest of December, they will appear to be super-close in the post-sunset night sky.

It’s called a “great conjunction” because Jupiter and Saturn are the two largest planets in the solar system, and to the naked eye they’ll look like a single bright star.

Colin Huggins, a keen amateur astronomer from Blythburgh, said to see this first-hand will be "totally different" from seeing it on TV or in books.

Stowmarket Mercury: To the left of the picture is the crescent moon, the bright object to the left of the chimney pot is the planet Jupiter, and slightly higher and to its left is the planet Saturn.To the left of the picture is the crescent moon, the bright object to the left of the chimney pot is the planet Jupiter, and slightly higher and to its left is the planet Saturn. (Image: Colin Huggins)

He took the photo above on Thursday, December 17 from the porch of Blythburgh Church.

"To the left of the picture you can see the crescent moon," said Mr Huggins.

"The bright object to the left of the chimney pot is the planet Jupiter, and slightly higher and to its left is the planet Saturn.

"Each evening the moon will move away to the left as the two planets get closer to each other. On Monday they will be so close that to the naked eye they will appear as a single object.

"Through binoculars or a small telescope you will be able to separate the two planets."

Mr Huggins said that subject to clear weather, they can be seen soon after sunset low in the south-west.

He advised keen stargazers to start looking from about 4pm and they will appear as the sky darkens.

He added: "Jupiter is 11 times as wide as the Earth and through a telescope, or good binoculars, you should be able to see its four largest moons. Saturn is almost as large and is characterised by its rings.

"Although appearing close in the sky, Jupiter is currently about 550 million miles from us, whilst Saturn is almost twice as far away."

The phenomenon has not been seen for 800 years - and it is believed that the event will next occur in 2080.