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Introduction to Constellations


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Title: Introduction to Constellations

Introduction to Constellations
  • Backyard Astronomy

The Night Sky
  • People have watched the night skies for millions
    of years. Some just out of curiosity. Some out
    of boredom. Some looking for portents, either
    good or bad.
  • However, the one thing that they all saw was
    that there was a pattern in the way the stars
    revolved around the heavens.

Finding Polaris and Why
  • Polaris (or the North Star) is where you want to
    start. Because Polaris is aligned with the
    Earths axis of rotation, it remains fixed, with
    all the other planets and stars appearing to move
    around it. It is the one star that remains fixed
    at all times.

The Stars Circling Polaris
Now That Youre Oriented, Its Time to Explore.
  • Youre pointed in the right direction, but what
    now. Stars and constellations move constantly
    and seasonally. What am I looking for? What you
    need is a star map.

Circumpolar Constellations
  • Circum means around (i.e. circumnavigate,
    circumference). Polar refers to the North Pole.
    Therefore, circumpolar constellations circle
    Polaris. This makes the 5 circumpolar
    constellations visible throughout the entire
    year. Lets look at each!

Ursa Minor
  • Once youve located Polaris, youre ready to
    identify your first constellation. Polaris is
    the last star located in the handle of the
    asterism, the Little Dipper. The name of the
    constellation that contains the Little Dipper is
    Ursa Minor or Little Bear.

Ursa Minor
  • Ursa Minor, also called the Little Dipper, is a
    circumpolar constellation. This means it never
    sets in the northern sky. The true figure
    represented by the stars is the Little Bear.
  • There are several mythological stories behind
    these famous constellations. In Greek myth, Zeus
    was having an affair with the lovely Callisto.
    When his wife, Hera, found out she changed
    Callisto into a bear. Zeus put the bear in the
    sky along with the Little Bear, which is
    Callisto's son, Arcas.

Ursa Minor
Ursa Minor
Ursa Minor
  • Named Stars
  • POLARIS (Alpha UMi)
  • KOCAB (Beta UMi)
  • Pherkad (Gamma UMi)
  • Yildun (Delta UMi)
  • Pherkad Minor (11 UMi)

Ursa Major
  • Ursa Major is probably the most famous
    constellation, with the exception of Orion. Also
    known as the Great Bear, it has a companion
    called Ursa Minor, or Little Bear. Everyone
    living in the Northern Hemisphere has probably
    spotted the easily recognized portion of this
    huge constellation. The body and tail of the bear
    make up what is known as the Big Dipper.
  • Several different cultures saw a big bear in the
    sky. The ancient Greeks had a few different
    stories to explain how the animal ended up there.
    In one story, Hera discovered Zeus was having an
    affair with Callisto and turned her into a bear.
    Zeus put her in the sky along with her son,
    Arcas, who became the Little Bear.

Ursa Major
The Big Dipper
Ursa Major
  • Named Stars
  • DUBHE (Alpha UMa)
  • MERAK (Beta UMa)
  • PHAD (Gamma UMa)
  • MEGREZ (Delta UMa)
  • ALIOTH (Epsilon UMa)
  • MIZAR (Zeta UMa)
  • ALKAID (Eta UMa)
  • Talitha (Iota UMa)
  • Tania Borealis (Lambda UMa)
  • Tania Australis (Mu UMa)
  • Alula Borealis (Nu UMa)
  • Alula Australis (Xi UMa)
  • Muscida (Omicron UMa)
  • Muscida (Pi 1 UMa)
  • Muscida (Pi 2 UMa)

  • Perhaps second only to the Big Dipper in Ursa
    Major, the constellation of Orion is one of the
    most recognizable patterns of stars in the
    northern sky. Orion, the hunter, stands by the
    river Eridanus and is accompanied by his faithful
    dogs, Canis Major and Canis Minor. Together they
    hunt various celestial animals, including Lepus,
    the rabbit, and Taurus, the bull. According to
    Greek mythology, Orion was in love with Merope,
    one of the Seven Sisters who form the Pleiades,
    but Merope would have nothing to do with him.
    Orion's tragic life ended when he stepped on
    Scorpius, the scorpion. The gods felt sorry for
    him, so they put him and his dogs in the sky as
    constellations. They also put all of the animals
    he hunted up there near him. Scorpius, however,
    was placed on the opposite side of the sky so
    Orion would never be hurt by it again.
  • From the northern hemisphere, the three bright
    stars (Alnitak, Alnilam and Mintaka) in a
    straight line that form Orion's Belt are easily
    visible on the southern horizon in winter
    evenings. The bright star that forms Orion's left
    shoulder is Betelgeuse. The name of this star
    means "The Armpit of the Central One" in Arabic,
    which shows that like many other constellations,
    Orion was recognized across many cultures.

  • Named Stars
  • BETELGEUSE (Alpha Ori)
  • RIGEL (Beta Ori)
  • BELLATRIX (Gamma Ori)
  • MINTAKA (Delta Ori)
  • ALNILAM (Epsilon Ori)
  • ALNITAK (Zeta Ori)
  • Nair al Saif (Iota Ori)
  • SAIPH (Kappa Ori)
  • Meissa (Lambda Ori)
  • Tabit (Pi 3 Ori)
  • Tabit (Pi 2 Ori)
  • Tabit (Pi 4 Ori)
  • Tabit (Pi 1 Ori)
  • Thabit (Upsilon Ori)

Cassiopeia Queen of Ethiopia or Andromeda's
  • Cassiopeia was the wife of King Cepheus. She was
    very pretty, and would often boast that she and
    her daughter were more beautiful than the sea
    nymphs, the Nereids. They complained to Poseidon,
    who unleashed a monster onto Cepheus' land. In
    order to save their country, the king and queen
    sacrificed their daughter, Andromeda. Just before
    the monster, named Cetus, ate the princess,
    Perseus saved her. All five figures are
    represented in the sky as constellations.
  • Cassiopeia has a very distinct shape. She looks
    like a "W" or "M" in the sky, depending on where
    she is. Some legends say that Cassiopeia was
    chained into the sky and sometimes hangs
    upside-down to remind others not to be so

  • Named Stars
  • SHEDIR (Alpha Cas)
  • Caph (Beta Cas)
  • Ruchbah (Delta Cas)
  • Segin (Epsilon Cas)
  • Achird (Eta Cas)
  • Marfak (Theta Cas)
  • Marfak (Mu Cas)

Cepheus King of Ethiopia or Andromeda's Father
  • Cepheus is one of the oldest constellations in
    the night sky. This house-shaped constellation is
    named after an ancient king of a land called
    Ethiopia (different from the current country,
    Ethiopia). He was married to the beautiful
    Cassiopeia and had a daughter, Andromeda.
  • In Greek mythology, Cassiopeia boasted that she
    and her daughter were more beautiful than the
    Nereids. They complained to the sea god Poseidon,
    who sent a monster to destroy Cepheus' land. The
    king and queen offered their daughter to the
    monster, but she was saved by Perseus.

  • Named Stars
  • ALDERAMIN (Alpha Cep)
  • Alfirk (Beta Cep)
  • Alrai (Gamma Cep)
  • Herschel's "Garnet Star" (Mu Cep)
  • Alkurhah (Xi Cep)
  • Al Kalb al Rai (Rho 2 Cep)

  • Draco the dragon, is only present in the Northern
    Hemisphere, so those living in the Southern
    Hemisphere will never see this long
  • The easiest way to spot Draco is by finding his
    head. It consists of four stars in a trapezoid,
    burning brightly just north of Hercules. From
    there, the tail slithers through the sky,
    eventually ending between the Big and Little
    Dippers. It can be difficult to trace Draco in
    the night sky. From the head, follow the body
    north towards Cepheus. It suddenly shifts south
    and west, ending up between the two dippers. The
    end of the constellation is held by Thuban, which
    was the pole star over 4,000 years ago.

  • Named Stars
  • THUBAN (Alpha Dra)
  • Rastaban (Beta Dra)
  • ETAMIN (Gamma Dra)
  • Nodus Secundus (Delta Dra)
  • Tyl (Epsilon Dra)
  • Aldhibah (Zeta Dra)
  • Ed Asich (Iota Dra)
  • Gianfar (Lambda Dra)
  • Arrakis (Mu Dra)
  • Kuma (Nu 2 Dra)
  • Grumium (Xi Dra)
  • Alsafi (Sigma Dra)
  • Dsiban (Psi 1 Dra)

About 4000 years ago, the star Thuban was the
North Star. Since then, precession of the Earth's
axis has changed where the North Pole points, so
the North Star is now Polaris. In another 10,000
years or so, the North Star will be Vega.
Signs of the Zodiac
  • Ecliptic Constellations

As the Sun traverses the ecliptic path, it
appears to move against a band of 12 ancient
constellations called the Zodiac
Ecliptic Constellations
Ecliptic Constellations
Aquarius The Water Bearer
  • In Greek mythology Aquarius was Ganymede,
    "cup-bearer to the gods". Alpha Aquarii
    ("Sadalmelik") and beta Aquarii ("Sadalsuud") are
    twin supergiants with nearly identical names. The
    names mean, respectively, "The Lucky One of the
    King" and "The Luckiest of the Lucky". Gamma
    Aquarii shares in the good fortune "Sadachbia"
    "The Lucky Star of Hidden Things" Incidentally,
    if the "Age of Aquarius" was celebrated in the
    1960s, the real event is still some 600 years
    off at that time Aquarius will contain the
    vernal equinox, marking the return of the Sun
    into the northern celestial hemisphere.

Aquarius The Water Bearer
Aries the Ram
  • Aries, "The Ram", is an ancient constellation
    which was of considerable importance since the
    sun passed through it at the vernal equinox.
  • This point has now moved into Pisces, but the
    vernal equinox is still known as the First Point
    of Aries. In another six hundred years the point
    will have moved into Aquarius.
  • The Ram in question may have been the one whose
    golden fleece was the object of Jason's quest.
  • There is some reason to believe that the Greeks
    just took over a much older horned animal at this
    time of the year the horn being a symbol for
    fecundity, renewal, and so on. As the Sun came
    into this constellation, at the vernal equinox,
    the year itself was being renewed.

Aries the Ram
Cancer The Crab
  • The name comes from the Latin cancer means
    crab. The crab in question is the one sent by
    Hydra to attack Heracles. It was only a bit part,
    but one which secured its immortality.

Gemini The Twins
  • Gemini, the Twins, are really only
    half-brothers. They share the same mother (Leda)
    but have different fathers. Castor's father was a
    king of Sparta, Tyndareus - who would be chased
    from his throne but later rescued by Heracles
    (who nevertheless wound up killing him). The
    father of Pollux was none other than Zeus, or
    Jupiter. Zeus visited Leda on her wedding night
    in the guise of a swan. Thus the twins would be
    born. (In fact two twins came from this double
    union, but let's not complicate the matter even

Leo The Lion
  • The first on the list of Heracles' labors was
    the task of killing the Nemean Lion, a giant
    beast that roamed the hills and the streets of
    the Peloponnesian villages, devouring whomever it
    met. The animal's skin was impervious to iron,
    bronze, and stone. Heracles' arrows harmlessly
    bounced off the lion his sword bent in two his
    wooden club smashed to pieces. So Heracles
    wrestled with the beast, finally choking it to
    death. He then wrapped the lion's pelt about him
    it would protect him from the next labor killing
    the poisonous Hydra.

Libra The Scales
  • Libra means "The Scales" or "Balance", so named
    because when the zodiac was still in its infancy,
    some four thousand years ago, the sun passed
    through this constellation at the autumnal
    equinox (21 September). At the two equinoxes
    (Spring and Autumn) the hours of daylight and
    darkness are equal. As a symbol for equality, the
    constellation came to represent Justice in
    several middle Eastern cultures. However, the
    Greeks had a different perspective at one time
    Scorpius, which lies just to the east, was much
    larger, and the stars that make up Libra were
    then known as the Claws of the Scorpion.


Pisces The Fish
  • Pisces is an ancient constellation derived, some
    say, from the story of the terrible Greek god
  • (This is not the Chinese word for "big wind",
    which - in English - is of course spelled
    "typhoon". The French, however, spell this word
    "typhon", which adds to the confusion. It is
    possible that the Chinese borrowed the word from
    the Greek. The modern Greek equivalent is spelled
    "tau upsilon phi omega nu" and means "cyclone".)

  • It was the Romans who named the constellation
    Sagittarius ("sagitta" is Latin for arrow'),
    although several stars carry Arabic names which
    identify just which portion of the constellation
    they represent. Sagittarius has a muddled
    history. In ancient times the asterism of three
    bright stars in a curved line was seen as a bow
    to some, leading both Greek and Roman writers to
    confuse the constellation with Centaurus.

Scorpius The Scorpion
  • As mentioned regarding Orion, Gaia may have sent
    the scorpion to kill the mighty hunter, as he had
    vowed to rid the earth of all wild animals. Or
    Apollo might have told Gaia of Orion's boast,
    fearful that Orion had designs on Apollo's sister
    Artemis. In any case it was Gaia who sent the
    scorpion to kill Orion. Later the animal would
    chase Orion across the heavens, but it could
    never catch him, for the scorpion was so placed
    that it would rise in the east only after Orion
    had safely disappeared over the western horizon.


Taurus The Bull
  • Is Taurus attacking Orion, the Hunter, or are
    the Horns of the Bull the real story? The horn
    was a symbol of fertility and bountiful riches in
    many cultures for thousands of years, and it is
    probably the case here, for the constellation
    would have announced the Vernal Equinox at around
    4000 BC.


Virgo The Virgin
  • Virgo is the second largest constellation (after
    Hydra). As a member of the Zodiac, Virgo has a
    number of ancient myths and tales. The Sun passes
    through Virgo in mid-September, and is therefore
    the constellation that announces the harvest.
    Virgo is often represented as a "maiden" (as its
    name indicates). In antiquity, she may have been
    Isis, the Egyptian protectress of the living and
    the dead and the principal mother goddess.