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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: 6:42  
clear_day Transit: 12:10  
SunsetSet: 17:40
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All Constellations » Hercules » 

ι Herculis (iota Herculis)

Altitude: 24.2°   Azimuth: 314.5°   Direction: North-West

ι Herculis is a variable and double sub-giant star in the constellation of Hercules.

ι Herculis visual magnitude is 3.8. Because of its moderate brightness, ι Herculis 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 ι Herculis is -0.005 arcsec per year in Right Ascension and 0.005 arcsec per year in Declination and the associated displacement for the next 100000 years is represented with the red arrow.

Image of ι Herculis (iota Herculis) star
DSS2 image of ι Herculis. The red arrow shows the motion of ι Herculis during the next 100000 years (-8.33 arcmin in Right Ascension and 8.33 arcmin in declination);

Key facts about ι Herculis


ι Herculis (iota Herculis) is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 24.2°
Azimuth: 314.5°
Direction: North-West

Celestial coordinates and finder chart of ι Herculis

ι Herculis is situated north of the celestial equator, as such, it is more easily visible from the northern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of ι Herculis are provided in the following table:

17h 39m 27s
+46° 00’ 23”

The simplified sky map below shows the position of ι Herculis in the sky:

Finder chart ι Herculis (iota Herculis) star
Simplified finder chart for ι Herculis (iota Herculis).

Visibility of ι Herculis from your location

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

ι Herculis (iota Herculis) is circumpolar and transits at 06:57 UTC (altitude: 84.5°)

Distance of ι Herculis from the Sun and relative movement

ι Herculis is distant 495.44 light years from the Sun and it is moving towards the Sun at the speed of 20 kilometers per second.

151.98 pc
495.44 ly
-20 km/s
-0.005 arcsec/year
0.005 arcsec/year

Spectral properties of ι Herculis

ι Herculis belongs to spectral class B3 and has a luminosity class of IV corresponding to a sub-giant star.


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

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

ι Herculis star system properties

ι Herculis 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 ι Herculis double sysyem:

116 arcsec

Alternative designations of ι Herculis

ι Herculis
(iota Herculis)
85 Herculis