Cassiopeia Constellation Facts
Cassiopeia is one of the brightest and most recognizable constellations in the night sky.
- Cassiopeia is visible all year in the Northern hemisphere.
- The constellation is visible in some northerly regions of the Southern hemisphere in late spring.
- The combination of its simple 'w' shape and the brightness of its stars makes Cassiopeia one of the most easily recognizable constellations in the night sky.
- If we were able to observe the sun from the nearest star system Alpha Centauri, it would appear in the constellation of Cassiopeia.
- Schedar is the brightest star in the constellation, it is 40 times larger in diameter than the sun.
- The supernova remnant "Cassiopeia A" lies within the boundaries of the constellation, supernova remnants are nebulas which form after the explosion of a large star.
- The Pacman Nebula, named after its resemblance to the old video game character, also lies within the constellation.
- Cassiopeia is one of the ancient constellations catalogued by the Greco-Roman astronomer Ptolomy almost 2,000 years ago.
Queen Cassiopeia spinning on her throne in the night sky.
Main Stars in the Cassiopeia Constellation
The number next to each star is its apparent magnitude, its brightness from our point of view on Earth, the lower the number the brighter the star in the night sky.
Also known as Epsilon Cassiopeiae, Segin is a blue giant star around 400 light years from Earth, it has a mass around 9 times that of the sun and a diameter around 6 times greater. The star has surface temperatures around 3 times greater than the sun and is around 2,500 times more luminous. Ruchbah
Also known as Delta Cassiopeiae, Ruchbah appears as a single star in the night sky but is actually a pair of binary stars, the larger of the two stars is a white subgiant around 4 times larger in diameter than the sun. Gamma Cassiopeiae
With no traditional name this star is known as Gamma Cassiopeiae, located around 550 light years from Earth Gamma Cassiopeiae is a blue subgiant with a mass almost 20 times greater than the sun and a diameter around 15 times greater. It is over 50,000 times more luminous than the sun with surface temperatures around 6 times hotter. Schedar
Also known as Alpha Cassiopeiae, Schedar is an orange giant around 230 light years from Earth and is the brightest star in the constellation, it has a mass around 4 times that of the sun and a radius around 40 times larger. Caph
Also known as Beta Cassiopeiae, Caph is a white-yellow giant star around 55 light years from Earth, it has around twice the mass of the sun with a radius around three and a half times larger.
Note: It may look like east and west are the wrong way wrong round on star charts but they are designed to be used as if they are being held above the head.
Finding Cassiopeia - Northern Hemisphere
Finding Cassiopeia - Southern Hemisphere