ANDROMEDA

| ANDROMEDA Chart | Midnight Culmination | Skylore | Description | Special Stars |
| Galaxies | Discussed in these Shows |

Constellation Data

  • Name: ANDROMEDA
  • Translation: Ethiopian Princess
  • Abbreviation: And
  • Genitive: Andromedae
  • Size: 19
  • Located Between: Cassiopeia, Pegasus
  • RA: 1hour
  • Decl: +40 degrees
  • Season: Fall
  • Midnight Culmination: 9 October
  • Pages where ANDROMEDA is discussed in Chet Raymo's 365 Starry Nights: 184,189-192,195



What is the Genitive form?
What is Right Ascension (RA)?
Is this constellation ever visible from my latitude? What is Declination?

Where should I look for a constellation on a date before or after its midnight culmination? What is Midnight Culmination?

Skylore

Andromeda (An-DRAW-ma-duh), the daughter of King Cepheus and Queen Cassiopeia of Ethiopia. When Cassiopeia boasted that Andromeda's beauty exceeded that of the sea nymphs, the nymphs prevailed upon Neptune, the god of the sea, to punish Cassiopeia. Neptune sent the sea monster Cetus (sometimes known more favorably as simply a whale) to ravage the kingdom of Cepheus. When Cepheus consulted an oracle for advice, he was informed that only the sacrifice of Andromeda to Cetus the Sea Monster would appease the gods. Thus chained to a rocky cliff, she was rescued by Perseus, who turned Cetus into stone by flashing the face of Medusa before the monster's eyes. Perseus was carried there just in time by the winged horse Pegasus. (As retold in the film "Clash of the Titans.") All of these constellations are located in the same region of the sky, as noted in the following poem.

Cicero, De natura deorum, II.110, trans. of Phenomena by Aratos of Soli (ca. 220 B.C.):
Cassiopeia with her obscure stars,
And next to her roams a bright shape, the sad
Andromeda, shunning her mother's sight.
The belly of the Horse touches her head,
Proudly he tosses high his glittering mane;
One common star holds their twin shapes joined
And constellations linked dissolubly.

Description

Andromeda contains one corner of the Great Square of Pegasus (the star Alpheratz). Andromeda's dress flows outward from the corner along three pairs of stars, with each pair slightly farther apart than the previous pair. Perhaps she is petting Pegasus, who bore the hero Perseus across the ocean on his mighty wings to save her from the sea monster Cetus.

[star chart]


Star chart created with Voyager II Software for Macintosh, published by Carina Software. This is just a taste of what Voyager can do! For info on Voyager II software, call Carina Software at (510) 355-1266, write them at 12919 Alcosta Blvd Suite #7, San Ramon, CA 94583, or visit Carina Software's home page and check out Voyager II for yourself.

Special Stars

Alpheratz means the navel of the horse, and recalls a time when the star was assigned to the constellation Pegasus. The star that is now Alpha-Andromedae was once Delta-Pegasi. Magnitude: 2.1. Distance: 72 LY.

Table of 25 Brightest Stars.
What is apparent stellar magnitude?

Galaxies

On one side of Andromeda's dress is a wedding present from Perseus, a patch of light called M31 or the Andromeda galaxy. The great galaxy in Andromeda shines at mag. 3.5.
[androm.gif]
This beautiful spiral galaxy is the most distant object visible to the naked eye, yet the closest major galaxy to the Milky Way, about 2,200,000 light years away.

Nearby are two small satellight galaxies, M32 (Elliptical galaxy), mag. 8.2. The other is NGC 205 (Elliptical galaxy), mag. 9.4.

Now, all the stars that are visible to the naked eye lie within our own Milky Way galaxy. This means that the stars that make up all the constellations, including Virgo and Leo and Coma Berenices, are stars of our own galaxy. The galaxies we see in these constellations are not actually located in the constellations, they are only viewed along the same line of sight. Were we to actually go to another galaxy, even the Andromeda galaxy (which is the closest major galaxy to the Milky Way, only 2.2 million light years away), then the stars of the Milky Way would not be distinguishable. It makes no sense to talk of Andromeda or Virgo as seen from another galaxy, since from another galaxy any observer would see all of the Milky Way stars together, just as we see a small patch of fuzzy light when we look at the Andromeda galaxy. It is not that Andromedans would see our constellation Andromeda differently; they would not distinguish it from the Milky Way at all.

The Andromeda galaxy has been known from early times. Al-Sufi described it as a "little cloud" in 964 AD. Simon Marius observed it in 1612 through a telescope, and described it as like a flame of a candle. It was not easy for astronomers to understand what a galaxy looks like. Early viewers of the Andromeda galaxy did not imagine that it was a star system like our own. Christian Huygens (HOY-gens) thought it was a hole in the heavens through which we might peer into the luminous regions beyond. Edmond Halley agreed, suggesting that the light came from a region of perpetual day, a shining ether filled with the light that originated on the first day of creation, before the formation of the Sun, Moon and stars. In 1845 Lord Rosse, using his great reflecting telescope, first resolved it into stars. In the 1920s Edwin Hubble--using the 100-inch telescope at Mount Wilson--used Cepheid variable stars to show that the Andromeda galaxy lay beyond the Milky Way. Thus Hubble established that the "nebulae" or cloudy spots which could be resolved into stars are actually external galaxies.

What are Galaxies?
Table of Messier Objects.
What is apparent Magnitude?

Discussed in these Shows

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