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: 4:50  
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All Constellations » Eridanus » 

Achernar - α Eridani (alpha Eridani)

Achernar, also designated as α Eridani (alpha Eridani), is a variable main-sequence star in the constellation of Eridanus.

Achernar visual magnitude is 0.46, making it the 9th brightest star in the sky. Thanks to its high brightness, Achernar 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 Achernar:

Achernar - α Eridani (alpha Eridani) is below the horizon from Greenwich, United Kingdom edit_location_alt.

Celestial coordinates and finder chart of Achernar

Achernar 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 Achernar are provided in the following table:

01h 37m 42s
-57° 14’ 12”

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

Finder chart Achernar - α Eridani (alpha Eridani) star
Simplified finder chart for Achernar - α Eridani (alpha Eridani).

Visibility of Achernar from your location

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

Achernar - α Eridani (alpha Eridani) is currently not visible from Greenwich, United Kingdom edit_location_alt

Digitized Sky Survey image of Achernar

The image below is a photograph of Achernar 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 Achernar is 0.095 arcsec per year in Right Ascension and -0.035 arcsec per year in Declination and the associated displacement for the next 1000 years is represented with the red arrow.

Image of Achernar - α Eridani (alpha Eridani) star
DSS2 image of Achernar. The red arrow shows the motion of Achernar during the next 1000 years (1.58 arcmin in Right Ascension and -0.58 arcmin in declination);

Distance of Achernar from the Sun and relative movement

Achernar is distant 143.74 light years from the Sun and it is moving far from the Sun at the speed of 16 kilometers per second.

44.09 pc
143.74 ly
16 km/s
0.095 arcsec/year
-0.035 arcsec/year

Spectral properties of Achernar

Achernar belongs to spectral class B3 and has a luminosity class of V corresponding to a main-sequence star.


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

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

Alternative designations of Achernar

α Eridani
(alpha Eridani)