SkyEye

Cassiopeia

The Queen

Abbreviation:Cas
Genitive:Cassiopeiae
Origin:[antiquity]
Fully Visible:12°S – 90°N

In Greek mythology, King Cepheus and Queen Cassiopeia of Æthiopia (what we call the Upper Nile region) had a daughter named Andromeda. Cassiopeia boasted that she and her daughter was more beautiful than the Nereids, the sea nymphs who often accompanied Poseiden, god of the seas. As punishment, Poseiden sent a sea monster, Cetus, to ravage the coast of Æthopia. In desperation, Cepheus consulted an oracle who informed him that to appease Poseiden, Cepheus must sacrifice his daughter Andromeda to the sea monster. Thus, Andromeda was stripped naked and chained to the rocks on the coast of the sea. Fortunately for her, Perseus was passing by, having just slain the Gorgon, Medusa. He killed the sea monster and set Andromeda free, claiming her as his bride.

The now-obsolete constellation Custos Messium stands off to the left. Old star atlases show the keeper of the harvest pointing at the queen.

The constellation of Cassiopeia

Notable Features

Visible Named Stars
α Cas Schedar This second-magnitude star is the brightest one in the constellation and is actually a four-star system.
β Cas Caph The second-brightest star in the constellation is only marginally dimmer than the brightest.
δ Cas Ruchbah This star appears as Ksora in Antonín Bečvář's Atlas of the Heavens — Ⅱ Catalogue 1950.0. The derivation of the name is unknown but it may be from the Arabic al‑ẓuhr meaning 'the back'.
ε Cas Segin This star belongs to a class called Be stars, rapidly-rotating B stars surrounded by gas and dust and whose spectra contain emission lines.
ζ Cas Fulu This is another unusual B-type star, a Slowly Pulsating B (SPB) star.
η Cas Achird William Herschel discovered the binary nature of this star in 1779. The origin of the name is unknown.
υ² Cas Castula This barium star is fifth magnitude.
Other Interesting Stars
HD 17156 Nushagak Located not far from 50 Cas, this eighth-magnitude star is known to have at least one exoplanet.
Deep Sky Objects
M52 This open cluster can be seen through binoculars.
M103 This is another open star cluster which is easy to observe through binoculars.
C8 In order to see this tenth magnitude open cluster, optical aids are required. Its number in the New General Catalogue is 559.
C10 Binoculars are necessary to view this young open cluster of several hundred stars. It is also known as NGC 663.
C11 Bubble Nebula This is a faint emission nebula and a medium-size telescope is required to observe it. It is located near open cluster M52 and is also catalogued as NGC 7635.
C13 Owl Cluster Discovered by William Herschel in 1787, the Owl Cluster (NGC 459) is a rich open cluster which is easily observable through binoculars.
C17 This dwarf spheroidal galaxy is a companion of the Andromeda Galaxy. A medium-size telescope is necessary to see this tenth magnitude object which is also known as NGC 147.
C18 This is another dwarf spheroidal galaxy and satellite of Andromeda Galaxy. NGC 185 is slightly easier to see than C17.
Meteor Shower Radiants
007 PER Perseids This August meteor shower is perhaps the most famous of them all. The meteors are fast and bright with many leaving trains, producing more colours than any other shower. Comet 109P/Swift-Tuttle is associated with this shower and since its return in 1992, this meteor shower has produced fine spectacles.