Your guide to the Solar System and the night sky
🌎 Location: Greenwich, United Kingdom [change]

Nunki - σ Sagittarii (sigma Sagittarii)

Nunki, also designated as σ Sagittarii (sigma Sagittarii), is a double main-sequence star in the constellation of Sagittarius.

Nunki visual magnitude is 2.02, making it the 50th brightest star in the sky. Thanks to its high brightness, Nunki 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 Nunki:

2.02
Main-sequence
Nunki - σ Sagittarii (sigma Sagittarii) is below the horizon from Greenwich, United Kingdom [change].

Celestial coordinates and finder chart of Nunki

Nunki is situated south of the celestial equator, as such, it is more easily visible from the southern emisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of Nunki are provided in the following table:

18h 55m 15s
-26° 17’ 48”
9.56°
-12.43°
Sagittarius

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

Finder chart Nunki - σ Sagittarii (sigma Sagittarii) star
Simplified finder chart for Nunki - σ Sagittarii (sigma Sagittarii).

Visibility of Nunki from your location

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

Today's Nunki - σ Sagittarii (sigma Sagittarii) rise, transit and set times from Greenwich, United Kingdom [change] are the following (all times relative to the local timezone Europe/London):

Azimuth: 116.3°
Max altitude: 12.2°
Azimuth: 243.7°
Nunki - σ Sagittarii (sigma Sagittarii) is below the horizon from Greenwich, United Kingdom

Digitized Sky Survey image of Nunki

The image below is a photograph of Nunki 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 Nunki is 0.013 arcsec per year in Right Ascension and -0.054 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of Nunki - σ Sagittarii (sigma Sagittarii) star
DSS2 image of Nunki. The red arrow shows the motion of Nunki during the next 10000 years (2.17 arcmin in Right Ascension and -9.00 arcmin in declination);

Distance of Nunki from the Sun and relative movement

Nunki is distant 224.21 light years from the Sun and it is moving towards the Sun at the speed of 11 kilometers per second.

68.78 pc
224.21 ly
-11 km/s
0.013 arcsec/year
-0.054 arcsec/year

Spectral properties of Nunki

Nunki belongs to spectral class B2 and has a luminosity class of V corresponding to a main-sequence star.

-2.17
B2V
14087K

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

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

Nunki star system properties

Nunki 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 Nunki double sysyem:

2.02
9.42
7.4
309 arcsec

Alternative designations of Nunki

Nunki
σ Sagittarii
(sigma Sagittarii)
34 Sagittarii
SAO187448
SAO187448