Cetus constellation: how to find it, when to see it and what is in it
In short
Cetus (Cet) is a equatorial constellation covering 1,231 square degrees, number 4 of 88 by size. Its brightest star is Diphda, a yellow giant, magnitude 2.0. It is best seen in the evening in December. Over London it rises and sets and is well placed in its season. Its neighbours in the sky: Aquarius, Aries, Eridanus, Fornax, Pisces, Sculptor, Taurus.
Area: 1,231 square degrees, 4 of 88 · Neighbours: Aquarius, Aries, Eridanus, Fornax, Pisces, Sculptor, Taurus · Updated 10 October 2026
How to find Cetus
- 1
When to look
The best time is in December in the evening: in the south, around 20:29.
- 2
Use the neighbours
Find it from the neighbouring constellations: Aquarius, Aries, Eridanus, Fornax.
- 3
Brightest stars
The brightest stars of the figure: Diphda (2.0ᵐ), Menkar (2.5ᵐ), Mira (3.0ᵐ).
When it is visible over London
| Month | Where and when | Conditions |
|---|---|---|
| January | in the south, around 18:26 | in the evening |
| February | in the southwest, around 18:29 | in the evening |
| March — july | — | not visible, behind the Sun |
| August | in the southeast, around 04:18 | before dawn |
| September | in the south, around 03:28 | before dawn |
| October — november | in the south, around 01:34 | around midnight |
| December | in the south, around 20:29 | in the evening |
Stars of the constellation
| Star | What it is | Magnitude |
|---|---|---|
| Diphda · β Cet | yellow giant | 2.0ᵐ |
| Menkar · α Cet | red giant | 2.5ᵐ |
| Mira · ο Cet | red giant | 3.0ᵐ |
| η Cet | orange giant | 3.5ᵐ |
| Kaffaljidhma · γ Cet | white main-sequence star | 3.5ᵐ |
| τ Cet | yellow main-sequence star | 3.5ᵐ |
| ι Cet | orange giant | 3.6ᵐ |
| θ Cet | orange giant | 3.6ᵐ |
Cetus FAQ
When is the best time to see Cetus?
Where is Cetus in the sky?
What is the brightest star in Cetus?
Neighbouring and other constellations
Related
Constellation lines: Stellarium, CC BY-SA · star names: IAU WGSN, CC BY 4.0