Cygnus

Cygnus (the swan) is a northern constellation. It was one of Ptolemy's 48 constellations, and is also one of the 88 modern constellations. Because of the pattern of its main stars, it is sometimes known as the Northern Cross (in contrast to the Southern Cross).

The bird extends over the summer Milky Way, appearing to fly south.

Cygnus
Abbreviation	Cyg
Genitive	Cygni
Meaning in English	the Swan
Right ascension	20.62 h
Declination	42.03°
Visible to latitude	Between 90° and -40°
On meridian	9 p.m., September 10
Area  - Total	Ranked 16th 804 sq. deg.
Number of stars with apparent magnitude < 3	4
Brightest star  - Apparent magnitude	Deneb (α Cyg) 1.25
Meteor showers	October Cygnids[?] Kappa Cygnids[?]
Bordering constellations	Cepheus Draco Lyra Vulpecula Pegasus Lacerta

Table of contents 1 Star map 2 Notable features 3 Notable deep sky objects 4 History and Mythology

Star map

Notable features

Cygnus contains several bright stars.

Deneb, α Cygni, is an extremely brilliant star, very prominent despite its distance (1 800 light years). The blue supergiant forms the swan's tail, the upper end of the Northern Cross, and one of the vertices of the so-called "Summer Triangle".

Albireo, β Cygni, is at the swan's beak. It is one of the most beautiful double stars of the sky, a golden star easily distinguishable in a small telescope from its blue companion.

Another interesting star is 61 Cygni. This star has one of the highest proper motions of any star in the sky (except the Sun) and was accordingly one of the first to have its distance measured. It is 11.4 light years, one of the closest stars to our solar system.

The star 16 Cygni B[?] is an extrasolar planetary system with one confirmed planet 1.5 times the mass of Jupiter.

Cygnus also contains the X-ray source Cygnus X-1, which is considered to be one of the most likely black hole candidates.

Notable deep sky objects

Several star clusters and nebulae are found in Cygnus due to its position on the Milky Way. NGC 7000, the North America Nebula[?], is found a bit to the east of Deneb. Its resemblance to the continent is best appreciated in photographs.

History and Mythology

In Greek mythology, the constellation represents several different legendary swans. Zeus disguised himself as a swan to rape Leda, who gave birth to the Gemini, Helen of Troy, and Clytemnestra.

Orpheus was transformed into a swan after his murder, and was said to have been placed in the sky next to his lyre.

Finally, it is said that a youth named Cygnus was the lover of the ill-fated Phaethon. After Phaethon was killed trying to drive the chariot of the sun, Cygnus searched desperately for his body in the river Eridanus where it had fallen. He dove so many times into the river that Zeus took pity on him and changed him into the waterbird that has since borne his name.

In Chinese mythology, the constellation Cygnus is the site of the once-a-year magpie bridge which connects the lovers Niu Lang and Zhi Nu (see Chinese Valentines Day).

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Cygnus is the generic name of the swans. See swan.

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Cygnus also is (or was) the name of a group implementing Cygwin, a port of various GNU tools to Microsoft Windows.