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public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
SunriseRise: 6:52  
clear_day Transit: 12:11  
SunsetSet: 17:31
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All Constellations » Sagittarius » 

Arkab Posterior - β2 Sagittarii (beta2 Sagittarii)

Altitude: -28.3°   Azimuth: 232.5°   Direction: South-West

Arkab Posterior, also designated as β2 Sagittarii (beta2 Sagittarii), is a giant star in the constellation of Sagittarius.

Arkab Posterior visual magnitude is 4.29. Because of its moderate brightness, Arkab Posterior should be easily visible from locations with dark skies, while it can be barely visible, or not visible at all, from skies affected by light pollution.

The proper motion of Arkab Posterior is 0.097 arcsec per year in Right Ascension and -0.054 arcsec per year in Declination and the associated displacement for the next 1000 years is represented with the red arrow.

Image of Arkab Posterior - β2 Sagittarii (beta2 Sagittarii) star
DSS2 image of Arkab Posterior. The red arrow shows the motion of Arkab Posterior during the next 1000 years (1.62 arcmin in Right Ascension and -0.90 arcmin in declination);

Key facts about Arkab Posterior


Arkab Posterior - β2 Sagittarii (beta2 Sagittarii) is below the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: -28.3°
Azimuth: 232.5°
Direction: South-West

Celestial coordinates and finder chart of Arkab Posterior

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

19h 23m 13s
-44° 47’ 58”

The simplified sky map below shows the position of Arkab Posterior in the sky:

Finder chart Arkab Posterior - β2 Sagittarii (beta2 Sagittarii) star
Simplified finder chart for Arkab Posterior - β2 Sagittarii (beta2 Sagittarii).

Visibility of Arkab Posterior from your location

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

Arkab Posterior - β2 Sagittarii (beta2 Sagittarii) is currently not visible from Greenwich, United Kingdom edit_location_alt

Distance of Arkab Posterior from the Sun and relative movement

Arkab Posterior is distant 138.61 light years from the Sun and it is moving far from the Sun at the speed of 19 kilometers per second.

42.52 pc
138.61 ly
19 km/s
0.097 arcsec/year
-0.054 arcsec/year

Spectral properties of Arkab Posterior

Arkab Posterior belongs to spectral class F2 and has a luminosity class of III corresponding to a giant star.


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

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

Alternative designations of Arkab Posterior

Arkab Posterior
β2 Sagittarii
(beta2 Sagittarii)