Deneb - α Cygni (alpha Cygni)

Altitude: 76.5° Azimuth: 249.7° Direction: West-South-West

Deneb, also designated as α Cygni (alpha Cygni), is a variable and double supergiant star in the constellation of Cygnus.

Deneb visual magnitude is 1.25, making it the 18th brightest star in the sky. Thanks to its high brightness, Deneb is clearly visible when observed from locations with dark skyes, and should be also quite easily visible from light polluted areas.

The table below summarizes the key facts about Deneb:

Color of Deneb ⬤

Magnitude of Deneb 1.25

Class Supergiant

VISIBILITY RIGHT NOW

Deneb - α Cygni (alpha Cygni) is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 76.5°
Azimuth: 249.7°
Direction: West-South-West

Celestial coordinates and finder chart of Deneb

Deneb is situated north of the celestial equator, as such, it is more easily visible from the northern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of Deneb are provided in the following table:

Right Ascension J2000 20h 41m 25s

Declination J2000 +45° 16’ 49”

Galactic Longitude 84.28°

Galactic Latitude 2°

Constellation Cygnus

The simplified sky map below shows the position of Deneb in the sky:

Finder chart Deneb - α Cygni (alpha Cygni) star

Simplified finder chart for Deneb - α Cygni (alpha Cygni).

Visibility of Deneb from your location

Location: Greenwich, United Kingdom edit_location_alt
Latitude: 51° 28’ 47” N
Longitude: 0° 00’ 00” E
Timezone: Europe/London

Deneb - α Cygni (alpha Cygni) is circumpolar and transits at 03:40 UTC (altitude: 83.8°)

Digitized Sky Survey image of Deneb

The image below is a photograph of Deneb from the Digitized Sky Survey 2 (DSS2 - see the credits section) taken in the red channel. The area of sky represented in the image is 0.5x0.5 degrees (30x30 arcmins). The proper motion of Deneb is 0.003 arcsec per year in Right Ascension and 0.002 arcsec per year in Declination and the associated displacement for the next 100000 years is represented with the red arrow.

Image of Deneb - α Cygni (alpha Cygni) star

DSS2 image of Deneb. The red arrow shows the motion of Deneb during the next 100000 years (5.00 arcmin in Right Ascension and 3.33 arcmin in declination);

Distance of Deneb from the Sun and relative movement

Deneb is distant 3,227.72 light years from the Sun and it is moving towards the Sun at the speed of 5 kilometers per second.

Distance (parsec) 990.10 pc

Distance (light year) 3,227.72 ly

Heliocentric radial velocity -5 km/s

Proper Motion RA 0.003 arcsec/year

Proper Motion Dec 0.002 arcsec/year

Spectral properties of Deneb

Deneb belongs to spectral class A2 and has a luminosity class of I corresponding to a supergiant star.

Absolute magnitude -8.73

Spectral Type A2I

Color Index (B-V) 0.09

Temperature of Deneb 9125K

The red dot in the diagram below shows where Deneb is situated in the Hertzsprung–Russell diagram.

H-R diagram showing the position of Deneb. Attribution: Richard Powell / CC BY-SA

Deneb star system properties

Deneb is a visual double star which can be observed only with the help of very large telescopes. The table below shows key information about the Deneb double sysyem:

Main star magnitude 1.25

Secondary star magnitude 11.25

Magnitude difference 10

Separation 75.4 arcsec

Alternative designations of Deneb

Proper Name Deneb

Bayer designation α Cygni
(alpha Cygni)

Flamsteed designation 50 Cygni

Henry Draper Catalogue HD197345

SAO Catalogue SAO49941

Hipparcos Catalogue HIP102098

Durchmusterung Catalogue BD+44 3541

FK5 Catalogue 777

General Catalogue of Variable Stars Alp Cyg

Aitken Double Star Catalogue ADS14172

In Evidence

Other stars in Cygnus