The two planets won't be this close again until 2080 and then sometime after the year 2400. 

Stargazers are in for an extremely rare treat that only comes around once or twice in several lifetimes, if we're lucky. 

Jupiter and Saturn will align from December 16-25 closer than they have been since the 1200s, making them look like a double planet ... or from our vantage point, one very large star. That formation has been referred to as the Christmas Star or The Star of Bethlehem. 

This year, the two planets will be closest to each other on December 21, which also marks the winter solstice. A pretty cool way to welcome in the winter and holiday season, right? 

“Alignments between these two planets are rather rare, occurring once every 20 years or so, but this conjunction is exceptionally rare because of how close the planets will appear to one another,” said Rice University astronomer Patrick Hartigan in a statement. “You’d have to go all the way back to just before dawn on March 4, 1226, to see a closer alignment between these objects visible in the night sky."

For those of us north of the equator, the best time to view this wonder will be for an hour after sunset each evening. It will appear low in the western sky for only a short time before they move below the horizon. That time gets shorter the farther north you live from the equator. Luckily, the planets will be bright enough to see in the twilight hours, which may be your best shot at seeing them. 

“On the evening of closest approach on Dec. 21 they will look like a double planet, separated by only fifth the diameter of the full moon,” Hartigan explained. “For most telescope viewers, each planet and several of their largest moons will be visible in the same field of view that evening.”

This is a not-to-be-missed astronomical event, as it won't be back around for several decades (and it won't be serving as the Christmas Star). According to Hartigan, the next time Jupiter and Saturn will be this close together will be March of 2080, so some of us may be around to see it twice in one lifetime. After that, the planets won't put on this particular show until after the year 2400. So, unless we perfect cryogenic freezing or some such preservation technique, this is likely your only chance to ever see something this spectacular. 

Will you be checking out this cool planetary alignment? Let us know in the comments!