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: 4:46  
clear_day Transit: 12:57  
SunsetSet: 21:08 south
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All Constellations » Crux » 

Acrux - α1 Crucis (alpha1 Crucis)

Altitude: -25.1°   Azimuth: 187.1°   Direction: South

Acrux, also designated as α1 Crucis (alpha1 Crucis), is a multiple hypergiant star in the constellation of Crux.

Acrux visual magnitude is 1.33. Thanks to its high brightness, Acrux 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 Acrux:


Acrux - α1 Crucis (alpha1 Crucis) is below the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: -25.1°
Azimuth: 187.1°
Direction: South

Celestial coordinates and finder chart of Acrux

Acrux 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 Acrux are provided in the following table:

12h 26m 35s
-63° 05’ 57”

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

Finder chart Acrux - α1 Crucis (alpha1 Crucis) star
Simplified finder chart for Acrux - α1 Crucis (alpha1 Crucis).

Visibility of Acrux from your location

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

Acrux - α1 Crucis (alpha1 Crucis) is currently not visible from Greenwich, United Kingdom edit_location_alt

Digitized Sky Survey image of Acrux

The image below is a photograph of Acrux 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 Acrux is -0.036 arcsec per year in Right Ascension and -0.012 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of Acrux - α1 Crucis (alpha1 Crucis) star
DSS2 image of Acrux. The red arrow shows the motion of Acrux during the next 10000 years (-6.00 arcmin in Right Ascension and -2.00 arcmin in declination);

Distance of Acrux from the Sun and relative movement

Acrux is distant 320.55 light years from the Sun and it is moving towards the Sun at the speed of 11 kilometers per second.

98.33 pc
320.55 ly
-11 km/s
-0.036 arcsec/year
-0.012 arcsec/year

Spectral properties of Acrux

Acrux belongs to spectral class B0 and has a luminosity class of IV corresponding to a hypergiant star.


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

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

Acrux star system properties

Acrux is a visual double star which can be observed with the help of small or medium telescopes. The table below shows key information about the Acrux double sysyem:

4.4 arcsec

Alternative designations of Acrux

α1 Crucis
(alpha1 Crucis)