Spring Triangle

The Spring Triangle is an astronomical asterism involving an imaginary triangle drawn upon the celestial sphere, with its defining vertices at Arcturus, Spica, and Regulus.^[1] This triangle connects the constellations of Boötes, Virgo, and Leo. It is visible in the evening rising in the southeastern sky of the Northern Hemisphere between March and May and setting until August, while at morning rising and setting from November to the end of February.

George Lovi of Sky & Telescope magazine had a slightly different Spring Triangle, including the tail of Leo, with Denebola replacing Regulus. Although Denebola is dimmer, this triangle is more nearly equilateral.^[2]

These stars, together with Cor Caroli, form parts of a larger spring asterism called the Great Diamond.