The Summer Triangle is an imaginary triangle formed by the brightest stars of three constellations: Altair of Aquila, Deneb of Cygnus and Vega of Lyra. It is a beautiful formation of very bright stars that were widely used for navigation long before the GPS and other electronic navigation systems. This formation can be seen almost in the zenith or very close to it around the midnight of your local time, if your country does not use the daylight saving time.