It's Your Last Chance to See 'Jupiter's Triangle' in the Night Sky Til 2030

Monday, 09 April 2018 - 11:11AM
Monday, 09 April 2018 - 11:11AM
It's Your Last Chance to See 'Jupiter's Triangle' in the Night Sky Til 2030
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Image credit: NASA

Stargazing into the night sky with a powerful telescope is cool and all, but we prefer the kind of constellation tracking that can be done by normal people without expensive equipment. According to Hayden Planetarium astronomy lecturer Joe Rao, there is one triangular shape worth looking up for that we will be able to see throughout April. It includes one of the brightest stars in the sky and the largest planet in our solar system.

Rao is calling the shape the "Jupiter Triangle," because obviously, the planet gets top billing over a couple stars, and because it is the brightest.


But those supporting cast stars do in fact have names.

One is Arcturus, which ScienceAlert says is the fourth brightest star (36.7 light years away from our Sun).


The other is called Spica, and it's actually a two-star system that, because of its distance from Earth (260 light years), it appears as one point. The window for seeing the triangle is pretty wide, but you'll have to know where and when to look.

How to See It

If you're looking up on a night this week, 11 p.m. is your best bet to spot the "roughly isosceles" triangle.


"This Triangle appears to point toward the northeast, with the brilliant yellow-orange star Arcturus (magnitude –0.1) at the vertex," writes Rao in his column for


"But unlike the famous Summer Triangle, which is composed of fixed stars, the Jupiter Triangle will be in a constant state of flux in the coming weeks because Jupiter will has been slowly shifting its position against the background stars. Since March 9, Jupiter has been undergoing a retrograde (backward) motion and has shifted westward against the star background. As a result, it has been approaching Spica and will continue to do so until its retrograde motion ends on July 11. By then the two will appear 20 degrees apart giving the triangle a more streamlined and slender appearance."

Around mid-September, Rao says that Spica will become "too deeply immersed in the sunset glow to be seen" and Jupiter will be out of sight by November. The Jupiter Triangle won't show up again until 2030.