Andromeda, the Princess Home



Andromeda was the daughter of Kepheus, the King of Ethiopia and his wife, Kasseopeia.  In order to save his people from the wrath of Poseidon (see Casseopeia), Kepheus chained Andromeda to the rocks by the sea to be devoured by the monster.  Fortunately for her, Perseus was flying by on winged sandals on his way back to Seriphos after killing the Gorgon Medusa, and he fell in love with her at first sight.  He promised Kepheus that he would rescue Andromeda on condition that he could marry her.  Kepheus agreed and, when the monster appeared, Perseus attacked it from above and killed it.  He returned her to her father and claimed her hand in marriage.  However Andromeda was betrothed to Kepheus's brother, Phineus, who objected strongly to her marrying Perseus.  Perseus solved the problem very easily by uncovering the head of the Medusa which turned Phineus and all his followers to stone.  He married Andromeda and within a year she had born him a son, Perses, who became the ancestor of all the Persian kings.  Eventually Andromeda bore him a daughter and five sons.  Their great-grandson was to be Herakles the greatest hero.
After their deaths, both Perseus and Andromeda were immortalised in the stars along with Kepheus, Kasseopeia, and the monster (Cetus).

The stars of Andromeda are not particularly striking.  The three brightest (α, β, and γ) are all of magnitude close to 2.1, the rest are fainter.  Mirach (β) is distinctly orange-red in colour, and Almaak, (γ) is a nice binary with an orange primary and a white (or slightly cyan) secondary separated by 9 arc-seconds.  (See footnote.)  R-Andromedae is a Mira-type variable which is exceptionally red and varies between magnitudes 6 and 15.

The best known object in the constellation is, of course, M31, the Andromeda Galaxy.  It is a member of the local group, larger than the Milky Way, and has two easily identifiable satellite galaxies, M52 and NGC205.  Although visible to the naked eye in a dark sky, it is a difficult telescopic object.  It is very large, covering 3° by 1°, and has a low surface brightness, so it needs a large aperture and low magnification — indeed binoculars are generally better than a telescope.

NGC 752 is an inconspicuous open cluster, 50 arc-minutes across.  NGC 7662 is a planetary nebula although the central star is very faint.

Footnote
My picture fails to bring out the orange colour of the primary because it is over-exposed in order to register the fainter secondary.  This in turn is probably more blue than it should be.  This illustrates the difficulty of rendering colours faithfully in images.




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