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Spotting a single planet with the naked eye might seem out of this world – but wait until you see four of them.

Skygazers are in for a celestial treat this week, as Venus, Mars, Jupiter and Saturn form a row in the sky in a 'planet parade'.

Experts say the best viewing window is between 5am and 6am over the coming days, after the planets rise above the horizon but just before the Sun follows after them.

In the southern hemisphere, the planets will be visible at the same time of the month but further east and at a steeper angle. 

Joining the four planets in their neat line in the last week of April will be the moon, appearing further south, just right of Saturn. 

Members of the public won't need a telescope to view the planets, which will be best viewed in clear skies free of cloud. 

In a sky full of stars, the planets can be identified by their distinct lack of twinkling. Stars twinkle, while planets usually shine steadily. 

The last time Saturn, Jupiter, Mars and Venus lined up like this was back in 2020, and, before that, in 2016 and 2005. 

Jake Foster, an astronomy education officer at Royal Museums Greenwich, told MailOnline that the alignment will be viewable through to early May. 

All the UK public will have to do will be 'face to the east before sunrise' and look for four bright points of light. low on the horizon.

'The four planets will be visible in the early mornings just before sunrise, which will be just before 6am BST on April 20,' Foster said.

'Sunrise will creep ever earlier as the days progress, so it is best to view this alignment sooner rather than later. 

'The tricky part will be catching the planets in the relatively short space of time between when they rise above the horizon and when the Sun follows after them. 

'This allows us a window of time between 5 and 6am BST most mornings from April 20 onwards to view the planets in a neat line across the sky.' 

Telling the planets apart with the naked eye is relatively simple to do, Foster added. 

'Venus will be noticeably the brightest of all four planets, shining a bright white light. Jupiter will be the second brightest, also shining white in colour. Saturn will be clearly fainter than the other three, due to its much further distance from the Sun.

'Mars will have the most distinctive difference from the others because of its colouration, appearing as a bright orange point of light to the naked eye.'   

According to NASA, the two brightest planets in the sky, Venus and Jupiter, are also set for their own ultra-close conjunction at the end of the month, on April 30.

This will be similar to the meetup of Mars and Saturn that happened earlier this month on April 4, where they appeared 'a couple of finger widths apart'.  

Since April 4, Saturn has been increasing its separation from Mars each day, just as Jupiter makes itself seen by popping over the horizon just before dawn, leading to what is set to be a stunning planetary alignment. 

'By mid-month, Jupiter is starting to rise in the pre-dawn hour, making for a quartet of planets, strung out in a line across the morning sky,' NASA says.

'Heading into the last week of April, Jupiter will be high enough above the horizon in the hour before sunrise to make it more easily observed.' 

Although they appear close as viewed from Earth, the planets are of course still millions of miles apart during an alignment. 

They only appear to move closer, or farther apart, in the sky as our view of them across the solar system changes from month to month. 

Also, planetary alignment depends on our viewpoint – so if three planets are in the same region of sky from Earth's point of view, they are not necessarily in the same region of sky form the sun's point of view. 

'Alignment is therefore an artefact of a viewpoint and not something fundamental about the planets themselves,' said Dr Christopher S. Baird, assistant professor of physics at West Texas A&M University. 

Dr Baird also said that planets in our solar system never line up in one perfectly straight-line 'like they show in the movies'.

'If you look at a two-dimensional plot of the planets and their orbits on a piece of paper you may be lead to believe that all the planets will circle around to the same line eventually.

'In reality, the planets do not all orbit perfectly in the same plane. Instead, they swing about on different orbits in three-dimensional space. For this reason, they will never be perfectly aligned.'  

An even more impressive alignment – dubbed the 'most spectacular of the year' – is set to take place in a couple of months.

On June 24, all the other planets in our solar system – Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune – will align the same region of pre-dawn sky. 

While Mercury, Venus, Mars, Jupiter and Saturn will be visible to the naked eye in good conditions, a telescope might be needed to discern Neptune and Uranus, according to Vito Technology, developer of the Star Walk app.