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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: 7:48  
clear_day Transit: 11:49  
SunsetSet: 15:50 south
sunny DaytimeWhat's Visible Now?
All Constellations » Ophiuchus » 

20 Ophiuchi

Altitude: 25.2°   Azimuth: 157.2°   Direction: South-South-East

20 Ophiuchi is a sub-giant star in the constellation of Ophiuchus.

20 Ophiuchi visual magnitude is 4.65. Because of its moderate brightness, 20 Ophiuchi 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 20 Ophiuchi:


20 Ophiuchi is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 25.2°
Azimuth: 157.2°
Direction: South-South-East

Celestial coordinates and finder chart of 20 Ophiuchi

20 Ophiuchi 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 20 Ophiuchi are provided in the following table:

16h 49m 50s
-10° 46’ 59”

The simplified sky map below shows the position of 20 Ophiuchi in the sky:

Finder chart 20 Ophiuchi star
Simplified finder chart for 20 Ophiuchi.

Visibility of 20 Ophiuchi 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 20 Ophiuchi 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: 100.8°
Max altitude: 27.7°
Azimuth: 259.2°

Digitized Sky Survey image of 20 Ophiuchi

The image below is a photograph of 20 Ophiuchi 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 20 Ophiuchi is 0.096 arcsec per year in Right Ascension and -0.093 arcsec per year in Declination and the associated displacement for the next 1000 years is represented with the red arrow.

Image of 20 Ophiuchi star
DSS2 image of 20 Ophiuchi. The red arrow shows the motion of 20 Ophiuchi during the next 1000 years (1.60 arcmin in Right Ascension and -1.55 arcmin in declination);

Distance of 20 Ophiuchi from the Sun and relative movement

20 Ophiuchi is distant 120.56 light years from the Sun and it is moving towards the Sun at the speed of 1 kilometers per second.

36.98 pc
120.56 ly
-1 km/s
0.096 arcsec/year
-0.093 arcsec/year

Spectral properties of 20 Ophiuchi

20 Ophiuchi belongs to spectral class F7 and has a luminosity class of IV corresponding to a sub-giant star.


The red dot in the diagram below shows where 20 Ophiuchi is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of 20 Ophiuchi. Attribution: Richard Powell / CC BY-SA

Alternative designations of 20 Ophiuchi

20 Ophiuchi