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A Complete Guide to the Solar System and the Night Sky
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public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
SunriseRise: 6:44  
clear_day Transit: 12:10  
SunsetSet: 17:38
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All Constellations » Crux » 

θ1 Crucis (theta1 Crucis)

Altitude: -40.1°   Azimuth: 144.8°   Direction: South-East

θ1 Crucis is a double star in the constellation of Crux.

θ1 Crucis visual magnitude is 4.33. Because of its moderate brightness, θ1 Crucis 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 θ1 Crucis is -0.15 arcsec per year in Right Ascension and 0.008 arcsec per year in Declination and the associated displacement for the next 1000 years is represented with the red arrow.

Image of θ1 Crucis (theta1 Crucis) star
DSS2 image of θ1 Crucis. The red arrow shows the motion of θ1 Crucis during the next 1000 years (-2.50 arcmin in Right Ascension and 0.13 arcmin in declination);

Key facts about θ1 Crucis


θ1 Crucis (theta1 Crucis) is below the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: -40.1°
Azimuth: 144.8°
Direction: South-East

Celestial coordinates and finder chart of θ1 Crucis

θ1 Crucis 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 θ1 Crucis are provided in the following table:

12h 03m 01s
-63° 18’ 46”

The simplified sky map below shows the position of θ1 Crucis in the sky:

Finder chart θ1 Crucis (theta1 Crucis) star
Simplified finder chart for θ1 Crucis (theta1 Crucis).

Visibility of θ1 Crucis from your location

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

θ1 Crucis (theta1 Crucis) is currently not visible from Greenwich, United Kingdom edit_location_alt

Distance of θ1 Crucis from the Sun and relative movement

θ1 Crucis is distant 229.74 light years from the Sun and it is moving towards the Sun at the speed of 2 kilometers per second.

70.47 pc
229.74 ly
-2 km/s
-0.15 arcsec/year
0.008 arcsec/year

Spectral properties of θ1 Crucis

θ1 Crucis belongs to spectral class A θ1 Crucis is also a so called metallic star.


The red dot in the diagram below shows where θ1 Crucis is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of θ1 Crucis. Attribution: Richard Powell / CC BY-SA

θ1 Crucis star system properties

θ1 Crucis 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 θ1 Crucis double sysyem:

4.5 arcsec

Alternative designations of θ1 Crucis

θ1 Crucis
(theta1 Crucis)