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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
north SunriseRise: 7:50  
clear_day Transit: 11:50  
SunsetSet: 15:49 south
sunny DaytimeWhat's Visible Now?
All Constellations » Scorpius » 

18 Scorpii

Altitude: 21.3°   Azimuth: 137.8°   Direction: South-East

18 Scorpii is a variable and double main-sequence star in the constellation of Scorpius.

18 Scorpii visual magnitude is 5.5. Because of its reltive faintness, 18 Scorpii should be visible only from locations with dark skyes, while it is not visible at all from skyes affected by light pollution.

The table below summarizes the key facts about 18 Scorpii:


18 Scorpii is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 21.3°
Azimuth: 137.8°
Direction: South-East

Celestial coordinates and finder chart of 18 Scorpii

18 Scorpii is situated close to the celestial equator, as such, it is at least partly visible from both hemispheres in certain times of the year. Celestial coordinates for the J2000 equinox as well as galactic coordinates of 18 Scorpii are provided in the following table:

16h 15m 37s
-08° 22’ 09”

The simplified sky map below shows the position of 18 Scorpii in the sky:

Finder chart 18 Scorpii star
Simplified finder chart for 18 Scorpii.

Visibility of 18 Scorpii from your location

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

Today's 18 Scorpii rise, transit and set times from Greenwich, United Kingdom edit_location_alt are the following (all times relative to the local timezone Europe/London):

Azimuth: 98.4°
Max altitude: 30.2°
Azimuth: 261.6°

Digitized Sky Survey image of 18 Scorpii

The image below is a photograph of 18 Scorpii 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 18 Scorpii is 0.234 arcsec per year in Right Ascension and -0.501 arcsec per year in Declination and the associated displacement for the next 1000 years is represented with the red arrow.

Image of 18 Scorpii star
DSS2 image of 18 Scorpii. The red arrow shows the motion of 18 Scorpii during the next 1000 years (3.90 arcmin in Right Ascension and -8.35 arcmin in declination);

Distance of 18 Scorpii from the Sun and relative movement

18 Scorpii is distant 45.72 light years from the Sun and it is moving far from the Sun at the speed of 11 kilometers per second.

14.03 pc
45.72 ly
11 km/s
0.234 arcsec/year
-0.501 arcsec/year

Spectral properties of 18 Scorpii

18 Scorpii belongs to spectral class G2 and has a luminosity class of V corresponding to a main-sequence star.


The red dot in the diagram below shows where 18 Scorpii is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of 18 Scorpii. Attribution: Richard Powell / CC BY-SA

18 Scorpii star system properties

18 Scorpii 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 18 Scorpii double sysyem:

25.8 arcsec

Alternative designations of 18 Scorpii