The Summer Triangle is an astronomical asterism involving an imaginary triangle drawn on the northern hemisphere's celestial sphere, with its defining vertices at Altair, Deneb, and Vega. This triangle connects the constellations of Aquila, Cygnus, and Lyra. In astronomy, an asterism is a recognized pattern of stars seen in Earths sky which is neither an official constellation nor a true star cluster. ... The celestial sphere is divided by the celestial equator. ... Altair (α Aql / α Aquilae / Alpha Aquilae / Atair ) is the brightest star in the constellation Aquila and the twelfth brightest star in the nighttime sky, at visual magnitude 0. ... Deneb (α Cyg / α Cygni / Alpha Cygni) is the brightest star in the constellation Cygnus and one of the brightest stars in the night sky, with apparent magnitude 1. ... Orihime redirects here. ... Aquila (Latin for Eagle), is one of the 48 constellations listed by Ptolemy and is now also part of the list of 88 constellations acknowledged by the IAU. It lies roughly at the celestial equator. ... For other meanings of the word Cygnus, see Cygnus (disambiguation) Cygnus (from the Latin for swan) is a northern constellation. ... Lyra (Latin for Lyre) is one of the 48 constellations listed by Ptolemy, and is one of the 88 modern constellations recognized by the International Astronomical Union. ...

The English term was popularized by British astronomer Sir Patrick Moore in the 1950s, although he did not invent it. Austrian astronomer Oswald Thomas described these stars as "Grosses Dreieck" (Great Triangle) in the late 1920s and "Sommerliches Dreieck" (Summerly Triangle) in 1934. The asterism was remarked upon by J. J. Littrow, who described it as the "conspicuous triangle" in the text of his atlas (1866), and Bode connected the stars in a map in a book in 1816, although without label. This article is about Patrick Moore, the astronomer. ... Joseph Johann Littrow (March 13, 1781 – November 30, 1840) was an Austrian astronomer. ... Johann Elert Bode Johann Elert Bode (January 19, 1747 – November 23, 1826) was a German astronomer known for his contribution to the Titius-Bode law and his works to determine the orbit of Uranus, for which he also suggested the name. ...

The Summer Triangle lies virtually overhead at mid-northern latitudes during the summer months, but can also be seen during spring in the early morning. In the autumn the summer triangle is visible in the evening well until November. From the southern hemisphere it appears upside down and low in the sky during the winter months. Latitude, usually denoted symbolically by the Greek letter φ, gives the location of a place on Earth north or south of the Equator. ... Spring is one of the four seasons of temperate zones. ... Fall redirects here. ... Southern Hemisphere The Southern Hemisphere is the half of a planets surface (or celestial sphere) that is south of the equator (the word hemisphere literally means half ball). On Earth it contains five continents (Antarctica, Australia, most of South America, parts of Africa, and Asia) as well as four... Winter is one of the four seasons of temperate zones. ...

The stars of the Summer Triangle

A light year, abbreviated ly, is the distance light travels in one year: roughly 9. ... Orihime redirects here. ... Lyra (Latin for Lyre) is one of the 48 constellations listed by Ptolemy, and is one of the 88 modern constellations recognized by the International Astronomical Union. ... Deneb (α Cyg / α Cygni / Alpha Cygni) is the brightest star in the constellation Cygnus and one of the brightest stars in the night sky, with apparent magnitude 1. ... For other meanings of the word Cygnus, see Cygnus (disambiguation) Cygnus (from the Latin for swan) is a northern constellation. ... Altair (α Aql / α Aquilae / Alpha Aquilae / Atair ) is the brightest star in the constellation Aquila and the twelfth brightest star in the nighttime sky, at visual magnitude 0. ... Aquila (Latin for Eagle), is one of the 48 constellations listed by Ptolemy and is now also part of the list of 88 constellations acknowledged by the IAU. It lies roughly at the celestial equator. ...

See also

• Winter Triangle
• Qi Xi