Summer Triangle

The defining vertices of this imaginary triangle are at Altair, Deneb, and Vega, each of which is the brightest star of its constellation (Aquila, Cygnus, and Lyra, respectively).

Two small constellations, Sagitta and Vulpecula, lie between Aquila in the south of the triangle and Cygnus and Lyra to the north.

These are the same stars recognized in the Chinese legend of The Cowherd and the Weaver Girl, a story dating back some 2,600 years, celebrated in the Qixi Festival.

The stars also bear ceremonial significance in the related celebrations of Tanabata, Chilseok, and Thất Tịch, derived from Qixi.

Both Altair and Vega are bluish-white, rapidly-rotating A-type main sequence stars in the local neighbourhood of the sun.

Map of the Summer Triangle
Map of the Summer Triangle
The Summer Triangle in the context of the night sky , with dimmer stars fading out first and then fading in last