Cassiopeia
The W that circles the pole
Best on December–February evenings · far-northern sky (circumpolar for much of the northern hemisphere).
Cassiopeia is one of the most recognizable shapes in the northern sky: five bright stars in a distinct W (or M, depending on the season). Sitting opposite the Big Dipper across the pole, it's circumpolar from northern latitudes — always up, never setting.
How to find it
Look high in the north on autumn evenings, when the W rides nearly overhead. It sits on the far side of Polaris from the Big Dipper, so the two take turns: when the Dipper is low, Cassiopeia is high. Trace five fairly bright stars in a zigzag and you've got it.
Brightest stars
The W's stars are well matched. Orange Schedar (magnitude 2.23) and white Caph (2.27) are the brightest, with Navi (2.47) at the center of the zigzag and Ruchbah (2.68) marking another bend.
Worth seeing
The W shape itself is the sight — one of the few patterns as instantly knowable as the Big Dipper, and a handy signpost: the open side of the W points roughly toward the rich star fields of the autumn Milky Way.
Frequently asked
When is Cassiopeia visible?
It's circumpolar from mid-northern latitudes — visible on every clear night all year — and rides highest on autumn evenings.
What are the main stars in Cassiopeia?
Five form the W: orange Schedar (magnitude 2.23) and white Caph (2.27) are the brightest, with Navi, Ruchbah and Segin completing the zigzag.
How do I tell Cassiopeia from the Big Dipper?
They sit on opposite sides of Polaris, so they swap places through the night and the year — when the Dipper is low, the W of Cassiopeia is high, and vice versa.
Nearby constellations
Cepheus · Andromeda · Perseus · Ursa Minor · Draco · Cygnus · Aries · Auriga