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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: 7:41  
clear_day Transit: 11:47  
SunsetSet: 15:53 south
sleep NighttimeWhat's Visible Now?
All Constellations » Ophiuchus » 

30 Ophiuchi

Altitude: -16.2°   Azimuth: 284.0°   Direction: West-North-West

30 Ophiuchi is a variable and double giant star in the constellation of Ophiuchus.

30 Ophiuchi visual magnitude is 4.82. Because of its moderate brightness, 30 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 30 Ophiuchi:


30 Ophiuchi is below the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: -16.2°
Azimuth: 284.0°
Direction: West-North-West

Celestial coordinates and finder chart of 30 Ophiuchi

30 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 30 Ophiuchi are provided in the following table:

17h 01m 03s
-04° 13’ 21”

The simplified sky map below shows the position of 30 Ophiuchi in the sky:

Finder chart 30 Ophiuchi star
Simplified finder chart for 30 Ophiuchi.

Visibility of 30 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 30 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: 94.2°
Max altitude: 34.3°
Azimuth: 265.8°

Digitized Sky Survey image of 30 Ophiuchi

The image below is a photograph of 30 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 30 Ophiuchi is -0.041 arcsec per year in Right Ascension and -0.075 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of 30 Ophiuchi star
DSS2 image of 30 Ophiuchi. The red arrow shows the motion of 30 Ophiuchi during the next 10000 years (-6.83 arcmin in Right Ascension and -12.50 arcmin in declination);

Distance of 30 Ophiuchi from the Sun and relative movement

30 Ophiuchi is distant 401.97 light years from the Sun and it is moving towards the Sun at the speed of 7 kilometers per second.

123.30 pc
401.97 ly
-7 km/s
-0.041 arcsec/year
-0.075 arcsec/year

Spectral properties of 30 Ophiuchi

30 Ophiuchi belongs to spectral class K4 and has a luminosity class of III corresponding to a giant star.


The red dot in the diagram below shows where 30 Ophiuchi is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of 30 Ophiuchi. Attribution: Richard Powell / CC BY-SA

30 Ophiuchi star system properties

30 Ophiuchi 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 30 Ophiuchi double sysyem:

94.1 arcsec

Alternative designations of 30 Ophiuchi

30 Ophiuchi