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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
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All Constellations » Cetus » 

Diphda - β Ceti (beta Ceti)

Altitude: 16.5°   Azimuth: 207.1°   Direction: South-South-West

Diphda, also designated as β Ceti (beta Ceti), is a variable giant star in the constellation of Cetus.

Diphda visual magnitude is 2.04, making it the 52th brightest star in the sky. Thanks to its high brightness, Diphda 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 Diphda:


Diphda - β Ceti (beta Ceti) is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 16.5°
Azimuth: 207.1°
Direction: South-South-West

Celestial coordinates and finder chart of Diphda

Diphda 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 Diphda are provided in the following table:

00h 43m 35s
-17° 59’ 12”

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

Finder chart Diphda - β Ceti (beta Ceti) star
Simplified finder chart for Diphda - β Ceti (beta Ceti).

Visibility of Diphda 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 Diphda - β Ceti (beta 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: 108.0°
Max altitude: 20.5°
Azimuth: 252.0°

Digitized Sky Survey image of Diphda

The image below is a photograph of Diphda 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 Diphda is 0.234 arcsec per year in Right Ascension and 0.033 arcsec per year in Declination and the associated displacement for the next 1000 years is represented with the red arrow.

Image of Diphda - β Ceti (beta Ceti) star
DSS2 image of Diphda. The red arrow shows the motion of Diphda during the next 1000 years (3.90 arcmin in Right Ascension and 0.55 arcmin in declination);

Distance of Diphda from the Sun and relative movement

Diphda is distant 95.77 light years from the Sun and it is moving far from the Sun at the speed of 13 kilometers per second.

29.38 pc
95.77 ly
13 km/s
0.234 arcsec/year
0.033 arcsec/year

Spectral properties of Diphda

Diphda 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 Diphda is situated in the Hertzsprung–Russell diagram.

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

Alternative designations of Diphda

β Ceti
(beta Ceti)