With her distinctive W shape Cassiopeia is one of the most recognizable constellations in the night sky.


Cassiopeia is part of the Andromeda/Perseus mythology. Cassiopeia was the mother of Andromeda and wife of Cepheus. She fell into misfortune because she claimed to rival the Nereids in beauty, and Poseidon sent a sea-monster to ravage her country; it was because of her that her daughter was exposed to the monster. She is represented near her daughter, seated on a chair.

She was turned to stone by Perseus when she objected to his marriage of Andromeda. She was placed into the sky by Neptune, but to add insult to injury she would appear upside down for certain parts of the year.

Points of Interest


The Milky Way

On a dark enough night you an see The Milky Way within Cassiopeia. This is the gas, dust and stars that make up our galaxy.

Tycho’s Supernova

In 1572 the astronomer Tycho observed a bright supenova slightly to the northwest of NGC 146, it grew so bright that it was visible by the naked eye for sixth months. Its appearance in the sky contradicted the idea that the sky did not change. Today the supernova is only faintly visible in large telescopes, however radio telescopes still receive strong signals.


  • Schedar

    Seems to have a pale pinkish tint.

  • Caph

    2.3 magnitude blue white giant.

  • Gamma Cassiopeiae

    The middle star in the W, is a blue giant variable star that varies from magnitude 3.0 to 1.6.

Double Stars

  • Iota Cassiopeiae
  • Struve 163
  • Eta Cassiopeiae
  • Burnham 1
  • Struve 3053
  • Sigma Cassiopeiae

Open Clusters

An open cluster is an irregular grouping of stars of common and possibly recent origin.

  • NGC 129

    A cluster of 50 stars in a region 20 light years across, located about 5,000 light years away from us.

  • NGC 225

    Contains 20 bright members and an estimated 50 or so dimmer ones. Located just under 2000 light years away.

  • NGC 436

    A small cluster of about 40 tars spread over four light years, about 4,000 light years away from us.

  • NGC 457

    A bright open cluster that lies close to phi Cas, which is southwest of delta Cas in the W of Cassiopeia. It contains around 200 stars and is located 9,000 light years away in a region 30 light years in diameter.

  • NGC 654

    A small cluster five light year in diameter about 4,000 light years away.

  • NGC 659

    30 bright stars in a region 10 light years in diameter, located 7,000 light years away.

  • NGC 659

    30 bright stars in a region 10 light years in diameter, located 7,000 light years away.

  • NGC 637

    A very small cluster of about 20 stars less than five light years wide, 5,000 light years away. 30 bright stars in a region 10 light years in diameter, located 7,000 light years away.

  • The Bubble Nebula (NGC 7635)

    It is located near M52 and although it has a high total brightness it is spread out over so much sky that its surface brightness is low.

  • M103

    A fan shaped, 7th magnitude cluster located northeast of delta Cas. Located 8,000 light years away from is and is about 15 million years old.

  • M52

    This 7th magnitude open cluster lies about 5 degrees northwest of beta Cas near the border of Cepheus. M52 consists of about 2000 stars in a region 15 light years in diameter. It lies about 5,000 light years away from us.

  • NGC 7789

    Located southwest of beta Cas, halfway between rho and sigma Cas. Its diameter is about the same as the Moon’s. Larger telescopes will be able see its 1000 stars. Most of the stars in this cluster have evolved into red giants or super giant stars, indicating that the cluster may be well over a billion years old. The cluster lies more than 5,000 light years away.

  • NGC 133 and NGC 146

    Northeast of beta Cas is kappa Cas, which is nearby these two open clusters. They require high powered telescope to be seen due to the richness of the Milky Way in this area.


  • Stars and Planets - Jay M. Pasachoff and Donald H. Menzel
  • Turn Left at Orion - Guy Consolmagno and Dan M. Davis
  • The Stargazer’s Guide to the Galaxy - Q.L. Pearce
  • Eratosthenes and Hyginus Constellation Myths - Robin Hard

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