出典:Wikipedia
出典:『Wikipedia』 (2011/03/28 11:29 UTC 版)
The Spring Triangle is an astronomical asterism involving an imaginary triangle drawn upon the celestial sphere, with its defining vertices at Arcturus, Spica, and alternately Denebola or Regulus. This triangle connects the constellations of Boötes, Virgo, and Leo. It is visible in the northern hemisphere night sky between March and May.