This weekend, three planets will nestle together in the western sky at twilight to form a rarely seen glowing triangle. With good timing and a bit of luck, you should be able to see it without a telescope.

Mercury, Venus, and Jupiter have been converging in the sky in the past month and will form their tightest clump on Sunday, May 26. This triple conjunction – visible from most of North America and Europe – will be easiest to see with the naked eye between 30 and 60 minutes after sunset, according to NASA.

Conjunctions of three planets are relatively rare. The last happened in May 2011, and another won't occur until October 2015. This year's gathering is impressively tight, though, and the next tightest won't come around until 2026, the editors of Sky & Telescope said in a statement.

Watch the trajectory of the planets in the Sky & Telescope video below: