Cygnus is a northern constellation. Its name is the Latinized Hellenic (Greek) word for swan. One of the most recognizable constellations of the northern summer and autumn, it features a prominent asterism known as the Northern Cross (in contrast to the Southern Cross). Cygnus was among the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations.
Albireo (β Cygni, designated by the Greek letter β in the diagram), a double star with blue and yellow components is at the "head". Deneb (α Cygni), its brightest star, is at the tail and is one star of the summer triangle.
Deep sky objects
Several star clusters and nebulae are found in Cygnus due to its position on the Milky Way. The North America Nebula (NGC 7000) is found a bit to the east of Deneb. Its resemblance to the continent is best appreciated in photographs. The Pelican Nebula (IC 5070) is nearby.
To the south of Epsilon Cygni is the Veil Nebula (NGC 6960, 6962, 6979, 6992, and 6995) which is an ancient supernova remnant covering approximately 3 degrees of the sky.
Also of note is the Crescent Nebula (NGC 6888), located between Gamma and Eta Cygni, which was formed by the Wolf-Rayet star HD 192163.
More supernovae have been seen in the Fireworks Galaxy (NGC 6946) than in any other galaxy.
The constellation also contains the X-ray source Cygnus X-1, which is now thought to be caused by a black hole accreting matter in a binary star system. The system is located close to the star Eta Cygni on star charts.
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