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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: 7:47  
clear_day Transit: 11:49  
SunsetSet: 15:50 south
sunny DaytimeWhat's Visible Now?
All Constellations » Sagittarius » 

ο Sagittarii (omicron Sagittarii)

Altitude: -16.9°   Azimuth: 103.9°   Direction: East-South-East

ο Sagittarii is a variable and double giant star in the constellation of Sagittarius.

ο Sagittarii visual magnitude is 3.77. Because of its moderate brightness, ο Sagittarii 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 ο Sagittarii:


ο Sagittarii (omicron Sagittarii) is below the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: -16.9°
Azimuth: 103.9°
Direction: East-South-East

Celestial coordinates and finder chart of ο Sagittarii

ο Sagittarii 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 ο Sagittarii are provided in the following table:

19h 04m 41s
-21° 44’ 30”

The simplified sky map below shows the position of ο Sagittarii in the sky:

Finder chart ο Sagittarii (omicron Sagittarii) star
Simplified finder chart for ο Sagittarii (omicron Sagittarii).

Visibility of ο Sagittarii 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 ο Sagittarii (omicron Sagittarii) 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: 111.7°
Max altitude: 16.8°
Azimuth: 248.3°

Digitized Sky Survey image of ο Sagittarii

The image below is a photograph of ο Sagittarii 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 ο Sagittarii is 0.08 arcsec per year in Right Ascension and -0.06 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of ο Sagittarii (omicron Sagittarii) star
DSS2 image of ο Sagittarii. The red arrow shows the motion of ο Sagittarii during the next 10000 years (13.33 arcmin in Right Ascension and -10.00 arcmin in declination);

Distance of ο Sagittarii from the Sun and relative movement

ο Sagittarii is distant 138.78 light years from the Sun and it is moving far from the Sun at the speed of 25 kilometers per second.

42.57 pc
138.78 ly
25 km/s
0.08 arcsec/year
-0.06 arcsec/year

Spectral properties of ο Sagittarii

ο Sagittarii belongs to spectral class G9 and has a luminosity class of III corresponding to a giant star.


The red dot in the diagram below shows where ο Sagittarii is situated in the Hertzsprung–Russell diagram.

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

ο Sagittarii star system properties

ο Sagittarii 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 ο Sagittarii double sysyem:

35.7 arcsec

Alternative designations of ο Sagittarii

ο Sagittarii
(omicron Sagittarii)
39 Sagittarii