σ Ophiuchi (sigma Ophiuchi)
σ Ophiuchi is a variable bright giant star in the constellation of Ophiuchus.
σ Ophiuchi visual magnitude is 4.34. Because of its moderate brightness, σ 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 σ Ophiuchi:
σ Ophiuchi (sigma Ophiuchi) is above the horizon from Greenwich, United Kingdom .
Celestial coordinates and finder chart of σ Ophiuchi
σ 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 σ Ophiuchi are provided in the following table:
The simplified sky map below shows the position of σ Ophiuchi in the sky:
Visibility of σ Ophiuchi from your location
Location: Greenwich, United Kingdom
Latitude: 51° 28’ 47” N
Longitude: 0° 00’ 00” E
Today's σ Ophiuchi (sigma Ophiuchi) rise, transit and set times from Greenwich, United Kingdom are the following (all times relative to the local timezone Europe/London):
Digitized Sky Survey image of σ Ophiuchi
The image below is a photograph of σ 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 σ Ophiuchi is 0.004 arcsec per year in Right Ascension and 0.007 arcsec per year in Declination and the associated displacement for the next 100000 years is represented with the red arrow.
Distance of σ Ophiuchi from the Sun and relative movement
σ Ophiuchi is distant 1,172.66 light years from the Sun and it is moving towards the Sun at the speed of 27 kilometers per second.
Spectral properties of σ Ophiuchi
σ Ophiuchi belongs to spectral class K2 and has a luminosity class of II corresponding to a bright giant star.
The red dot in the diagram below shows where σ Ophiuchi is situated in the Hertzsprung–Russell diagram.