Cassiopeia
Five bright stars forming a flattened W, circling the North Star and never setting from most northern latitudes. Cassiopeia is the easiest constellation to find after the Big Dipper.
Star chart · schematic positions
Drag to pan · dashed rings mark deep-sky objects · east is left
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Tap any labelled star in the chart to read its name, magnitude and spectral type.
Why it matters
Cassiopeia lies in the Milky Way's plane, so its background is crowded with star clusters and nebulae. It also contains Cassiopeia A, the strongest radio source in the sky outside the solar system — the remnant of a supernova that exploded around 1680.
How to find it tonight
- 1Look north on any clear night and find the W of five bright stars.
- 2Use the middle star of the W to point towards Polaris — the North Star — by following a line through it.
- 3In autumn the W stands nearly overhead; in spring it hangs low above the northern horizon.
- 4Scan the area with binoculars: the Milky Way passes right through, filling the view with stars.
Brightest stars on the chart
Schedar (α Cassiopeiae) · Caph (β Cassiopeiae) · Gamma Cassiopeiae (γ Cassiopeiae) · Ruchbah (δ Cassiopeiae)
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Figures are rounded averages from NASA, ESA and IAU reference data. Star positions on charts are schematic and approximate.