Your Guide to the Solar System and the Night Sky
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public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
north SunriseRise: 4:46  
clear_day Transit: 12:56  
SunsetSet: 21:07 south
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All Constellations » Sagittarius » 

Ascella - ζ Sagittarii (zeta Sagittarii)

Altitude: -47.6°   Azimuth: 280.9°   Direction: West

Ascella, also designated as ζ Sagittarii (zeta Sagittarii), is a multiple giant star in the constellation of Sagittarius.

Ascella visual magnitude is 2.6, making it the 99th brightest star in the sky. Thanks to its high brightness, Ascella is clearly visible when observed from locations with dark skyes, and should be also quite easily visible from light polluted areas.

The table below summarizes the key facts about Ascella:


Ascella - ζ Sagittarii (zeta Sagittarii) is below the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: -47.6°
Azimuth: 280.9°
Direction: West

Celestial coordinates and finder chart of Ascella

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

19h 02m 36s
-29° 52’ 49”

The simplified sky map below shows the position of Ascella in the sky:

Finder chart Ascella - ζ Sagittarii (zeta Sagittarii) star
Simplified finder chart for Ascella - ζ Sagittarii (zeta Sagittarii).

Visibility of Ascella 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 Ascella - ζ Sagittarii (zeta 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: 119.9°
Max altitude: 8.6°
Azimuth: 240.1°
Ascella - ζ Sagittarii (zeta Sagittarii) is below the horizon from Greenwich, United Kingdom

Digitized Sky Survey image of Ascella

The image below is a photograph of Ascella 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 Ascella is -0.015 arcsec per year in Right Ascension and -0.002 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of Ascella - ζ Sagittarii (zeta Sagittarii) star
DSS2 image of Ascella. The red arrow shows the motion of Ascella during the next 10000 years (-2.50 arcmin in Right Ascension and -0.33 arcmin in declination);

Distance of Ascella from the Sun and relative movement

Ascella is distant 89.05 light years from the Sun and it is moving far from the Sun at the speed of 22 kilometers per second.

27.31 pc
89.05 ly
22 km/s
-0.015 arcsec/year
-0.002 arcsec/year

Spectral properties of Ascella

Ascella belongs to spectral class A2 and has a luminosity class of III corresponding to a giant star.


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

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

Ascella star system properties

Ascella 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 Ascella double sysyem:

0.5 arcsec

Alternative designations of Ascella

ζ Sagittarii
(zeta Sagittarii)
38 Sagittarii