Constellation · Cassiopeia · Cas

Cassiopeia constellation: how to find it, when to see it and what is in it

northernbest in november4 bright stars

In short

Cassiopeia is five bright stars in a W (or an M, depending on its tilt) on the far side of Polaris, opposite the Big Dipper. For northern observers it never sets: on autumn and winter evenings it is high overhead, in spring low in the north. The Milky Way runs through it, so from a dark site the W is surrounded by countless faint stars and clusters.

Area: 598 square degrees, 25 of 88 · Neighbours: Andromeda, Camelopardalis, Cepheus, Lacerta, Perseus · Updated 10 October 2026

How to find Cassiopeia

1
Look for a W
Five stars of almost equal brightness — Schedar, Caph, Navi, Ruchbah and Segin — form a W or an M.
2
Check against Polaris
Cassiopeia and the Big Dipper sit on opposite sides of Polaris at roughly the same distance. When the Dipper is low, Cassiopeia is high, and vice versa.
3
Look along the Milky Way
From a dark site the W lies in the bright band of the Milky Way. Below it, towards Perseus, is the Double Cluster — a hazy patch to the eye and a field of stars in binoculars.

When it is visible over London

Month	Where and when	Conditions
January	in the north, around 17:41	in the evening
February — march	in the northwest, around 18:29	in the evening
April — july	in the northeast, around 04:31	before dawn
August	in the north, around 04:18	before dawn
September — november	in the north, around 02:28	around midnight
December	in the north, around 19:29	in the evening

Stars of the constellation

Star	What it is	Magnitude
Schedar · α Cas	orange giant	2.2ᵐ
Caph · β Cas	yellow-white giant	2.3ᵐ
Tiansi · γ Cas	blue-white subgiant	2.5ᵐ
Ruchbah · δ Cas	white giant	2.7ᵐ
Segin · ε Cas	blue-white giant	3.4ᵐ