Editing Summer Triangle (section)

{{Short description|Asterism}}
[[File:Map-summer-triangle.png|thumb|right|alt=Map of the Summer Triangle|Map of the Summer Triangle]]

The '''Summer Triangle''' is an astronomical [[asterism (astronomy)|asterism]] in the [[northern celestial hemisphere]]. The defining [[vertex (geometry)|vertices]] of this imaginary [[triangle]] are at [[Altair]], [[Deneb]], and [[Vega]], each of which is the [[list of brightest stars|brightest star]] of its [[constellation]] ([[Aquila (constellation)|Aquila]], [[Cygnus (constellation)|Cygnus]], and [[Lyra]], respectively). The greatest declination is  +45° and lowest is +9° meaning the three can be seen from all places in the Northern Hemisphere and from the home of most people resident in the Southern Hemisphere. The two stars in Aquila and Cygnus represent the head of an eagle and tail of a swan that looks east inscribed into the triangle and forming the [[Altitude (triangle)|altitude of the triangle]]. Two small constellations, [[Sagitta]] and [[Vulpecula]], lie between Aquila in the south of the triangle and Cygnus and Lyra to the north.