Tonight the stars of the Summer Triangle — Vega, Deneb and Altair — light up the eastern part of the evening sky and their blazing radiance is visible to the unaided eye even for observers from the most light-polluted areas. The Summer Triangle isn’t a constellation but an asterism, which is a noticeable group of stars, and consists of 3 stars in 3 constellations.
Vega is the brightest star in the eastern sky shining in the constellation Lyra the Harp. It is rather easy to find this constellation in the sky as it looks like an imaginary triangle of stars connected to a parallelogram. Vega marks the upper right vertex of the Summer triangle. The star’s name derives from the Arabic phrase “the falling vulture”.
Deneb, the brightest star in the constellation Cygnus the Swan, shines at the left vertex of the triangle. Name “Deneb” means “the tail of an animal” and refers to the tail of the mythical Swan that the constellation represents.
Altair is the most brilliant star in the constellation Aquila the Eagle and the second brightest in the Summer Triangle. The name of the star derives from Arabic phrase “the flying (eagle)”.
The Summer Triangle may help you to find the Milky Way in the sky as it passes right between the triangle’s stars Vega and Altair. Once you learn to detect the Summer Triangle, you can always spot this cloudy river of stars in the clear, dark evening sky. Whereas every star that might be seen with the naked eye belongs to our Milky Way galaxy, the term Milky Way is used to denote the cross-sectional view of the galactic disk.
The best time to see the Summer Triangle is July because its stars sparkle from dusk till dawn at mid-northern latitudes. Happy stargazing!