Introduction to Constellations

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Introduction to Constellations

• Backyard Astronomy

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Warm Up

• What is a constellation?
• What is a circumpolar constellation?
• Around what point do all the stars rotate?
• How do you locate Polaris?
• Name four things that make stargazing more
  comfortable?

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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.

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The Night Sky

• You need only to look up for a few hours to
  begin to see these same patterns yourself. Like
  the Sun, stars rise in the east and set later in
  the west. Planets follow this same pattern
  unless they are in a retrograde period, though
  these periods are not especially common.

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What You Need for Stargazing

• You dont really need anything, but some things
  are handy, like
• Complete darkness-Dont laugh, its not that
  easy to find. Rural area are slowly being
  urbanized, bringing their lights with them.
  Light pollution is a real problem.

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What You Need Darkness

• Darkness means getting away from the city when
  you can. Crowders Mountain, South Mountain, The
  Blue Ridge Parkway and several rural spots
  outside Matthews and Huntersville are still
  fairly dark. I recommend the Parkway in the Fall
  and Winter. The quantity of stars you see will
  take your breath.

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What You Need Darkness

• Darkness means keeping up with the phases of the
  moon, too. When the moon is waxing past half
  full, its quite hard to see.

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What You Need Star Map/ Planesphere

• It is handy to have a star map to help get you
  oriented. We will make one in here, so you get
  the idea, but laminated ones are nice and they
  are protected from dew and spilled drinks when
  your tripping around in the dark. Star Maps are
  also called planespheres. You can find them in
  hobby stores for a couple of bucks.

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What You Need Flashlight

• Well, you dont have to trip around in the dark.
  You can bring a flashlight! Theres one problem
  here though. It takes your eyes about 20-30
  minutes to get acclimated to the dark. Your
  pupils arent fully dilated until then, so a
  regular flashlight will never do. Your eyes will
  have to get acclimated every time you turn it on.
  To prevent this, your flashlight should have a
  red gel to protect your eyes. Red saran wrap
  with a rubber band works great . It works great
  for catching night crawlers too.

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What You Need Binoculars

• Binoculars dont have to be very strong to give
  you a much better, brighter view of the stars.
  Binoculars have the ability to gather light even
  at low magnifications. Even 4X ones will make a
  marked difference in the detail you can see.

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What You Need Telescope?

• No, you dont need a telescope, though they are
  fun. Telescopes require a certain amount of
  sophistication to set up and operate and they are
  not for everybody. There are some nice models
  available at affordable costs. The optics are
  available alone also if you want to build your
  own.

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What You Need Warm Clothes

• Youll be happy to know that the best time to
  look at stars is the least popular time of year
  to be outside, the winter. So, dress warmly.
  Remember that the nights are longer in the winter.

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Leonid An Aside

• I remember the 2002 Leonid meteor shower very
  well. The Leonid comes in November and that year
  it was really cold. I got up about 330 a.m.
  (yes, thats right) to have a look. It was
  incredible. Meteors were streaking across the
  sky every few seconds. Sometimes several at
  once. It was the best Leonid for over 35 years.
  I even woke my wife up to join me. We sat on the
  deck in sleeping bags and drank coffee. Its one
  of my happiest memories. Another Leonid of that
  magnitude is not expected again until 2098 or
  2131.

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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.

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Getting Oriented or Where the Hell is North?

• Yea, you have to find north. Its where Polaris
  (or North Star) is. Youll need a compass or
  major highway to orient yourself. I-77 is good
  because it runs due north and south. You can
  make a compass with a needle, magnet and a cup of
  water. Just rub the needle across a magnet (see
  your refrigerator) or leave it attached
  overnight. Then rub the needle across your nose
  and place it in the cup very gently. It will
  float. It will turn north.

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Figuring the Angle

• Once youve decided where north is (right
  ascension), face in that direction. Next you
  have to figure declination (up and down). Extend
  your arm and make a fist. Put the bottom of your
  fist on the horizon. The top of your fist is
  about 80 higher. Place your other fist on top of
  your first. Youve now measured 160 up from the
  horizon. Polaris is located between 250 and 300
  above the horizon. Polaris is faint, so look
  carefully!

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Another Way to Find Polaris

• If all that compass making and angle crap is
  just too complicated, there is another way to
  find Polaris. Find the Big Dipper (not a
  constellation). Most people recognize this
  asterism. The two stars that form the front of
  the cup of the dipper define a line pointing to
  Polaris.

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The Big Dipper
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The Stars Circling Polaris
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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.

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Now That Youre Oriented, Its Time to Explore.

• You also have access to software that provides
  you with the same information.

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Circumpolar Constellations

• Circum means around (i.e. circumcise,
  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!

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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.

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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.

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Ursa Minor
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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.

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Ursa Major
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Cassiopeia

• 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
  boastful.

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Cassiopeia
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Cepheus

• 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.

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Cepheus
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Draco

• Draco the dragon, is only present in the Northern
  Hemisphere, so those living in the Southern
  Hemisphere will never see this long
  constellation.
• 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.

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Draco
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Signs of the Zodiac

• Common Constellations

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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.

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Aquarius The Water Bearer
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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.

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Aries the Ram
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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.

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Cancer
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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
  more...)

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Gemini
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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.

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Leo
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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.

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Libra

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Pisces The Fish

• Pisces is an ancient constellation derived, some
  say, from the story of the terrible Greek god
  Typhon.
• (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".)

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Pisces
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Sagittarius

• 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.

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Sagittarius
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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.

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Scorpius

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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.

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Taurus

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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.

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Virgo