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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: 7:38  
clear_day Transit: 11:46  
SunsetSet: 15:54 south
sleep NighttimeWhat's Visible Now?
All Constellations » Cetus » 

21 Ceti

Altitude: 24.6°   Azimuth: 212.6°   Direction: South-South-West

21 Ceti is a sub-giant star in the constellation of Cetus.

21 Ceti visual magnitude is 6.16. Because of its reltive faintness, 21 Ceti should be visible only from locations with dark skyes, while it is not visible at all from skyes affected by light pollution.

The table below summarizes the key facts about 21 Ceti:


21 Ceti is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 24.6°
Azimuth: 212.6°
Direction: South-South-West

Celestial coordinates and finder chart of 21 Ceti

21 Ceti 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 21 Ceti are provided in the following table:

00h 54m 17s
-08° 44’ 26”

The simplified sky map below shows the position of 21 Ceti in the sky:

Finder chart 21 Ceti star
Simplified finder chart for 21 Ceti.

Visibility of 21 Ceti 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 21 Ceti 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: 98.7°
Max altitude: 29.8°
Azimuth: 261.3°

Digitized Sky Survey image of 21 Ceti

The image below is a photograph of 21 Ceti 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 21 Ceti is 0.018 arcsec per year in Right Ascension and -0.052 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of 21 Ceti star
DSS2 image of 21 Ceti. The red arrow shows the motion of 21 Ceti during the next 10000 years (3.00 arcmin in Right Ascension and -8.67 arcmin in declination);

Distance of 21 Ceti from the Sun and relative movement

21 Ceti is distant 379.07 light years from the Sun and it is moving far from the Sun at the speed of 45 kilometers per second.

116.28 pc
379.07 ly
45 km/s
0.018 arcsec/year
-0.052 arcsec/year

Spectral properties of 21 Ceti

21 Ceti belongs to spectral class G5 and has a luminosity class of IV corresponding to a sub-giant star.


The red dot in the diagram below shows where 21 Ceti is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of 21 Ceti. Attribution: Richard Powell / CC BY-SA

Alternative designations of 21 Ceti