'The Christmas Star' set to light up the night sky in Greece on December 21

Skywatchers are in for a treat.

What has become known as the “Christmas Star”, bright planets Jupiter and Saturn will be separated by only 0.1 degree and visible from around the globe in the western twilight sky on December 21.

To the naked eye, they will look like one, bright star.

“We’ll have to hasten to see Jupiter and Saturn, because they will disappear two-and-a-half hours after sunset, though Mars will be visible until midnight,” Stavros Avgoloupis, a professor of observational astronomy at the Aristotle University of Thessaloniki, told AMNA.

"Christmas Star"

The planets regularly appear to pass each other in the solar system, with the positions of Jupiter and Saturn being aligned in the sky about once every 20 years.

What makes this year’s spectacle so rare, then? It’s been nearly 400 years since the planets passed this close to each other in the sky, and nearly 800 years since the alignment of Saturn and Jupiter occurred at night.

While these two planets may appear close, they are still hundreds of millions of miles apart, according to NASA.

The timing of the occurrence couldn’t be more perfect.

If you miss this conjunction and want to see the planets with the same proximity, just higher in the sky, it won’t happen until March 15, 2080.