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  
clear_day Transit: 12:56  
SunsetSet: 21:02 south
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All Constellations » Eridanus » 

Acamar - θ1 Eridani (theta1 Eridani)

Acamar, also designated as θ1 Eridani (theta1 Eridani), is a variable and double giant star in the constellation of Eridanus.

Acamar visual magnitude is 3.24. Because of its moderate brightness, Acamar 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 Acamar:

Acamar - θ1 Eridani (theta1 Eridani) is below the horizon from Greenwich, United Kingdom edit_location_alt.

Celestial coordinates and finder chart of Acamar

Acamar 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 Acamar are provided in the following table:

02h 58m 15s
-40° 18’ 16”

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

Finder chart Acamar - θ1 Eridani (theta1 Eridani) star
Simplified finder chart for Acamar - θ1 Eridani (theta1 Eridani).

Visibility of Acamar from your location

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

Acamar - θ1 Eridani (theta1 Eridani) is currently not visible from Greenwich, United Kingdom edit_location_alt

Digitized Sky Survey image of Acamar

The image below is a photograph of Acamar 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 Acamar is -0.045 arcsec per year in Right Ascension and 0.019 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of Acamar - θ1 Eridani (theta1 Eridani) star
DSS2 image of Acamar. The red arrow shows the motion of Acamar during the next 10000 years (-7.50 arcmin in Right Ascension and 3.17 arcmin in declination);

Distance of Acamar from the Sun and relative movement

Acamar is distant 161.23 light years from the Sun and it is moving far from the Sun at the speed of 12 kilometers per second.

49.46 pc
161.23 ly
12 km/s
-0.045 arcsec/year
0.019 arcsec/year

Spectral properties of Acamar

Acamar belongs to spectral class A4 and has a luminosity class of III corresponding to a giant star.


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

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

Acamar star system properties

Acamar 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 Acamar double sysyem:

8.3 arcsec

Alternative designations of Acamar

θ1 Eridani
(theta1 Eridani)