Cassiopeia constellation
Cassiopeia (the Queen) is a constellation in the northern sky, best seen in the evening in November. Its brightest star is Schedar (magnitude 2.23). It contains the W. Cassiopeia covers 598 square degrees and is the 25th-largest of the 88 constellations.
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How to find Cassiopeia, step by step
Opposite the Big Dipper, on the other side of Polaris.
- Find Polaris, the North Star, using the Big Dipper (see the Polaris guide).
- Draw a line from Megrez, where the handle meets the bowl, through Polaris and continue about the same distance.
- You arrive at Cassiopeia: five bright stars in a W (or M, depending on the time of night). From mid-northern latitudes it never sets and is highest on autumn evenings.
Detailed star map of Cassiopeia
Facts
| Latin name | Cassiopeia (genitive: Cassiopeiae) |
|---|---|
| Abbreviation | Cas |
| Meaning | the Queen |
| Area | 598 square degrees (25th of 88) |
| Location | right ascension 1.0 h, declination +62° |
| Visible from | latitudes 90° N to 12° S (whole constellation) |
| Best month | November (at about 9 pm) |
| Brightest star | Schedar |
| Stars brighter than magnitude 6 | 94 |
| Named stars (IAU) | 7 |
| Messier objects | M52, M103 |
| Neighbors | Andromeda, Camelopardalis, Cepheus, Lacerta, Perseus |
How to find Cassiopeia
From 40° N (the USA, southern Europe, Japan) Cassiopeia is circumpolar: it never sets and is visible all night, all year, highest in the north about 68° above the horizon in November evenings. From 35° S (Australia, South Africa, Argentina) it stays below the horizon. The months before and after (October and December) are also good: then it is up a couple of hours earlier or later.
Cassiopeia borders Andromeda, Camelopardalis, Cepheus, Lacerta and Perseus.
Stars of Cassiopeia
Cassiopeia has 94 stars brighter than magnitude 6, the limit of the naked eye under a dark sky. These are the brightest:
| Star | Designation | Magnitude | Type | Distance |
|---|---|---|---|---|
| Schedar | α Cassiopeiae | 2.23 | K0IIIa | 231 ly |
| Caph | β Cassiopeiae | 2.27 | F2III-IV | 54 ly |
| — | γ Cassiopeiae | 2.47 | B0IVe | — |
| Ruchbah | δ Cassiopeiae | 2.68 | A5III-IV | 102 ly |
| Segin | ε Cassiopeiae | 3.38 | B3III | 466 ly |
| Achird | η Cassiopeiae | 3.44 | F9V+dM0 | 19 ly |
| Fulu | ζ Cassiopeiae | 3.66 | B2IV | 355 ly |
| — | 50 Cassiopeiae | 3.98 | A2V | — |
| — | κ Cassiopeiae | 4.16 | B1Ia | — |
| — | θ Cassiopeiae | 4.33 | A7V | — |
Deep-sky objects in Cassiopeia
Cassiopeia contains 2 objects from Charles Messier's catalog:
- Messier 52 (M52): open cluster, 7.3 mag
- Messier 103 (M103): open cluster, 7.4 mag
Printable Cassiopeia map and outline
A black and white version for printing and a plain outline of the Cassiopeia figure, useful for school projects, worksheets and learning to recognize the shape.
History
Cassiopeia is one of the 48 constellations listed by Ptolemy in the Almagest (2nd century AD). Its official boundary was drawn by Eugène Delporte for the International Astronomical Union in 1930.
Questions about Cassiopeia
What is the brightest star in Cassiopeia?
Schedar, at magnitude 2.23, about 231 light-years away.
When can you see Cassiopeia?
Cassiopeia is best seen in the evening in November. The whole constellation is visible from latitudes between 90° N and 12° S.
How many stars are in Cassiopeia?
94 stars in Cassiopeia are brighter than magnitude 6 and can be seen with the naked eye under a dark sky; 7 of them have official IAU names.
What does Cassiopeia mean?
Cassiopeia means “the Queen” in Latin. Its abbreviation is Cas and the genitive, used in star names such as α Cassiopeiae, is Cassiopeiae.
