During the year, there are times when the patterns in the sky form recognizable shapes. One of the easiest things to see during the summer months is the Summer Triangle. It is made up of the stars Altair, Deneb, and Vega, three of the brighter stars of the summer sky. Altair is the brightest star in the constellation Aquila, the Eagle; Deneb the brightest star of the constellation Cygnus, the swan, and Vega – the brightest star of the summer skies – in the constellation Lyra, the Lyre.
The Summer Triangle is considered an asterism, which is a pattern of stars which is either part of a whole constellation, or parts of several constellations. The Big Dipper is probably the most famous asterism.
In early summer these stars and their constellations rise before midnight, but during August they are directly overhead in the mid-evening skies, and is still visible low in the northwest before dawn.
Even though it’s the “Summer Triangle”, this asterism is visible from late spring into early winter, but it is most prominent during the summer months. Winter has it’s version of the triangle itself, with the stars Betelgeuse, Procyon, and Sirius.
So whatever the time of year, there’s a triangle above your head at all times. It’s up to you to decide if it’s equilateral, isosceles, or something else.