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Cygnus

The Swan

Abbreviation: Cyg
Genitive: Cygni
Origin: [antiquity]

The constellation of Cygnus

There are several swans from Greek mythology identified with this constellation, including Zeus (who disguised himself as a swan to seduce Leda who subsequently gave birth to the Gemini), Orpheus (who was transformed into a swan after his murder) and King Cycnus (who turned into a swan after he was killed by Achilles during the Trojan War).

The asterism composed of the stars α Cyg, β Cyg, γ Cyg, δ Cyg and ε Cyg is often called the 'Northern Cross'. It is not to be confused with the much smaller constellation Crux, the Southern Cross.

The first magnitude star Deneb forms another asterism, the 'Summer Triangle', with two other first magnitude stars, Altair and Vega.

Notable Features

Designation Name Description
α Cyg Deneb This first magnitude star forms one part of the asterism known as the 'Summer Triangle'. It sometimes appears as Arided (from the Arabic al‑ridf meaning 'the follower') in older star atlases and catalogues.
β Cyg Albireo Albireo shows up as a beautiful binary star of constrasting colours when viewed through binoculars or a telescope. This star appears as Menchir al Dedjadjet (from the Arabic minqār al‑dajājah meaning 'the beak of the hen') in Mohammad Al Achsasi Al Mouakket's calendarium.
γ Cyg Sadr
δ Cyg Fawaris
ε Cyg Aljanah This star sometimes appears as Gienah in older star atlases and catalogues.
π1 Cyg Azelfafage
61 Cyg Just visible to the naked eye, this is one of the closest stars to the Sun and the first one successfully observed for parallax.
M29 This is an open cluster, visible through binoculars.
M39 Binoculars are also required to see this open star cluster.
C15 Blinking Planetary This is a planetary nebula visible through telescopes. The central star is quite bright but averted vision will reveal the nebulosity.
C19 Cocoon Nebula The Cocoon Nebula requires optical aids to see this seventh magnitude combination emission/reflection nebula with accompanying star cluster.
C20 North America Nebula The North America Nebula is so called because in long exposure it takes the outline of the North American continent.
C27 Crescent Nebula A small telescope should reveal this faint emission nebula.
C33
C34
Veil Nebula These objects are part of the Cygnus Loop complex, a supernova remnant. The star that blew itself to bits exploded 5000-8000 years ago.
Cygnus X-1 Probably a black hole, this object is one of the strongest x-ray sources in the sky.