Jupiter, Saturn, and Mercury forming triangle in the sky this weekend

You won't want to miss this rare sight!

Updated: 11:58 PM EST Jan 8, 2021

Above video: Closest alignment of Jupiter, Saturn in nearly 800 yearsRight before Christmas, the two largest planets in our solar system formed a "double planet," an incredible spectacle that hasn't happened in more than 800 years. Well, soon one more planet will be joining them for another rare celestial sight. This weekend, Jupiter, Saturn, and Mercury will form a triangle for the first time since 2015, according to EarthSky.Dubbed a "planetary trio" or a "triple conjunction," the three planets will appear close together just after sunset from Jan. 8 through Jan. 11. Tonight, Mercury will start to move closer to Saturn, which will appear below Jupiter. So when's the best date to see the triple conjunction? The tightest grouping of these planets will occur on Sunday. The best way to catch the planetary trio is find a spot with an unobstructed view of the horizon, and look toward the direction of the sunset. It's important to start searching for the planets no later than 45 minutes after the sun sets because they will fall out of view beneath the horizon by nightfall, according to EarthSky. It might be difficult to spot the planets (especially Saturn, the dimmest of the three planets) while they're competing with the glow of the sunset. So it's a good idea to bring along binoculars or a telescope.Wondering what other celestial sights you can look forward to this year? Check out this complete list of full moon dates throughout 2021. Time to mark your calendars, skywatchers!