Cygnus (original) (raw)
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.
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| 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 (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 | vis mag | abs mag | spec type | distance (ly) | RA (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'; RA 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'; RA 20h 23.9m, Dec +48° 26'. |
| M39 (NGC 7092) | open cluster | About 50 stars in a loose grouping about 9° east and slightly north of Deneb. Magnitude 4.6; diameter 32'; RA 21h 32.2m, Dec +44° 20'. |