Your Guide to the Solar System and the Night Sky
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public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
north SunriseRise: 6:52  
clear_day Transit: 12:49  
SunsetSet: 18:46 south
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All Constellations » Cygnus » 

σ Cygni (sigma Cygni)

Altitude: 31.3°   Azimuth: 64.6°   Direction: East-North-East

σ Cygni is a variable supergiant star in the constellation of Cygnus.

σ Cygni visual magnitude is 4.23. Because of its moderate brightness, σ Cygni should be easily visible from locations with dark skyes, while it can be barely visible, or not visible at all, from skyes affected by light pollution.

The table below summarizes the key facts about σ Cygni:


σ Cygni (sigma Cygni) is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 31.3°
Azimuth: 64.6°
Direction: East-North-East

Celestial coordinates and finder chart of σ Cygni

σ Cygni 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 σ Cygni are provided in the following table:

21h 17m 25s
+39° 23’ 40”

The simplified sky map below shows the position of σ Cygni in the sky:

Finder chart σ Cygni (sigma Cygni) star
Simplified finder chart for σ Cygni (sigma Cygni).

Visibility of σ Cygni from your location

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

σ Cygni (sigma Cygni) is circumpolar and transits at 20:51 UTC (altitude: 77.9°)

Digitized Sky Survey image of σ Cygni

The image below is a photograph of σ Cygni 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 σ Cygni is 0.001 arcsec per year in Right Ascension and -0.003 arcsec per year in Declination and the associated displacement for the next 100000 years is represented with the red arrow.

Image of σ Cygni (sigma Cygni) star
DSS2 image of σ Cygni. The red arrow shows the motion of σ Cygni during the next 100000 years (1.67 arcmin in Right Ascension and -5.00 arcmin in declination);

Distance of σ Cygni from the Sun and relative movement

σ Cygni is distant 4,527.78 light years from the Sun and it is moving towards the Sun at the speed of 4 kilometers per second.

1,388.89 pc
4,527.78 ly
-4 km/s
0.001 arcsec/year
-0.003 arcsec/year

Spectral properties of σ Cygni

σ Cygni belongs to spectral class B9 and has a luminosity class of I corresponding to a supergiant star.


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

HR Diagram
H-R diagram showing the position of σ Cygni. Attribution: Richard Powell / CC BY-SA

Alternative designations of σ Cygni

σ Cygni
(sigma Cygni)