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public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
north SunriseRise: 6:52  
clear_day Transit: 12:49  
SunsetSet: 18:46 south
sunny DaytimeWhat's Visible Now
All Constellations » Aquila » 

Okab - ζ Aquilae (zeta Aquilae)

Altitude: 43.6°   Azimuth: 131.6°   Direction: South-East

Okab, also designated as ζ Aquilae (zeta Aquilae), is a variable and multiple hypergiant star in the constellation of Aquila.

Okab visual magnitude is 2.99. Thanks to its high brightness, Okab 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 Okab:


Okab - ζ Aquilae (zeta Aquilae) is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 43.6°
Azimuth: 131.6°
Direction: South-East

Celestial coordinates and finder chart of Okab

Okab 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 Okab are provided in the following table:

19h 05m 24s
+13° 51’ 47”

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

Finder chart Okab - ζ Aquilae (zeta Aquilae) star
Simplified finder chart for Okab - ζ Aquilae (zeta Aquilae).

Visibility of Okab 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 Okab - ζ Aquilae (zeta Aquilae) 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: 76.1°
Max altitude: 52.4°
Azimuth: 283.9°

Digitized Sky Survey image of Okab

The image below is a photograph of Okab 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 Okab is -0.005 arcsec per year in Right Ascension and -0.096 arcsec per year in Declination and the associated displacement for the next 1000 years is represented with the red arrow.

Image of Okab - ζ Aquilae (zeta Aquilae) star
DSS2 image of Okab. The red arrow shows the motion of Okab during the next 1000 years (-0.08 arcmin in Right Ascension and -1.60 arcmin in declination);

Distance of Okab from the Sun and relative movement

Okab is distant 83.21 light years from the Sun and it is moving towards the Sun at the speed of 25 kilometers per second.

25.52 pc
83.21 ly
-25 km/s
-0.005 arcsec/year
-0.096 arcsec/year

Spectral properties of Okab

Okab belongs to spectral class A0 and has a luminosity class of V corresponding to a hypergiant star.


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

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

Okab star system properties

Okab 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 Okab double sysyem:

158.6 arcsec

Alternative designations of Okab

ζ Aquilae
(zeta Aquilae)
NN 4095 A