A

David

Darling

Cygnus

Cygnus constellation

Cygnus. © 2003 Torsten Bronger.


Cygnus (abbreviation Cyg), the Swan, is a conspicuous northern constellation that lies east of Lyra and north of Vulpecula. The main stars form a cruciform asterism known as the Northern Cross – a familiar sight overhead in northern winter evening skies. See below for details of the constellation's brightest stars and interesting deep sky objects.

 

Northern Cross
The Northern Cross is an asterism consisting of five bright stars that make up the most prominent part of Cygnus. These stars are: Deneb (Alpha Cyg), Albireo (Beta Cyg), Sadr (Gamma Cyg), Delta Cyg, and Gienah (Epsilon Cyg).

 


Cygnus A

 

Cygnus A (3C405)

 

Cygnus A (3C 405) is the strongest extragalactic radio source and third strongest radio source in the sky (after the Sun and Cassiopeiae A). At one time believed to be the result of a collision of two galaxies, it has now been identified as a classic double-lobed radio galaxy that, at optical wavelengths, is a 15th magnitude cD galaxy (a supergiant elliptical) lying about one billion light-years away.

 


Brightest stars and other objects of interest in Cygnus

 

Stars in Cygnus brighter than magnitude 4.0
Star Visual mag. Abs. mag. Spectral type Distance (lt-yr) R.A. (h m s) Dec. (° ' ")
Alpha (Deneb) 1.25 -8.73 A2Iae 3,230 20 41 26 +45 16 49
Gamma (Sadr) 2.23 -6.12 F8Ib 1,520 20 22 14 +40 15 24
Epsilon (Gienah) 2.58 -0.94 K0III 165 20 46 13 +33 58 13
Delta 2.86 -0.74 B9.5IV+F1V 171 19 44 58 +45 07 51
Beta (Albireo) 3.05 -2.32 K3II+B0.5V 386 19 30 43 +27 57 35
Zeta 3.21 -0.12 G8III-IIIaBa 151 21 12 56 +30 13 37
Xi 3.72 -4.07 K5Ib-II 1,180 21 04 56 +43 55 40
Tau 3.73 2.13 F1IV 68 21 14 47 +38 02 44
Iota 3.76 0.88 A5Vn 122 19 29 42 +51 43 47
Kappa 3.80 0.91 K0III 123 19 17 06 +53 22 07
Eta 3.89 0.73 K0III 139 19 56 18 +35 05 00
Nu 3.94 -1.25 A1Vn 356 20 57 10 +41 10 02


Other objects of interest
Name Type of object Notes
61 Cygni star See separate entry
P Cygni star The prototype P Cygni star
SS Cygni star The prototype SS Cygni star
Cygnus X-1 star See separate entry
Blinking Nebula planetary nebula NGC 6826. See separate entry
NGC 7072 planetary nebula An object with an irregular shape and four bright condensations. Magnitude 13.9; diameter 0.8'; R.A. 21h 30.6m, Dec. -43° 09'
NGC 6960, 6992 diffuse nebula The western and eastern parts, respectively, of the Veil Nebula
North America Nebula diffuse nebula NGC 7000. See separate entry
Pelican Nebula diffuse nebula IC 5067, 5070. See separate entry
Great Rift dark nebula See separate entry
M29 (NGC 6913) open cluster A cluster of about 50 stars near Gamma Cyg. Magnitude 6.6; diameter 7'; R.A. 20h 23.9m, Dec. +48° 26'.
M39 (NGC 7092) open cluster About 50 stars in a loose grouping about 9o east and slightly north of Deneb. Magnitude 4.6; diameter 32'; R.A. 21h 32.2m, Dec. +44° 20'.


Constellations
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