Free constellation guide

How to find Cassiopeia by its W shape.

Cassiopeia is a five-star zigzag that can look like a W or an M, depending on how it is turned. For northern observers, it is one of the handiest large-scale patterns to recognise.

The pattern to recognise

Start with five reasonably bright stars making a bold zigzag. It is the changing angles between the stars—not a perfectly drawn letter—that matter. In the northern sky, Cassiopeia lies roughly opposite the Plough around the Pole Star, so the two patterns can become useful companions once each is familiar.

What a bright sky changes

Light pollution softens the fainter detail around Cassiopeia, but its five main stars often remain a useful outline. On a bright night, accept a simpler W and avoid filling in stars you cannot clearly see. As the sky gets darker, the constellation sits in a richer field of background stars.

Practise before you look up

Bortle Bounded helps you learn Cassiopeia one star at a time, then practise without labels or guide lines. It is one of the free lessons, with views for brighter and darker skies. Sky Lens provides a predicted guide from time, place and, in Compass and Live, the way your phone points; it does not identify stars from camera images.