Introduction to Constellations

1
Introduction to Constellations

• Backyard Astronomy

2
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.

3
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.

4
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.

5
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.

6
What You Need Star Map/ Planesphere

• It is handy to have a star map to help get you
  oriented.
• Star Maps are also called planespheres.
• You can find them in hobby stores for a couple of
  bucks.

7
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.

8
Getting Oriented or Where the Heck 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. Highway 17 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.

9
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!

10
Another Way to Find Polaris

• If all that compass making and angle junk is
  just too complicated, there is another way to
  find Polaris. Find the Big Dipper (part of 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.

11
The Big Dipper
12
The Stars Circling Polaris
13
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.

14
A Few Constellations...
15
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.

16
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.

17
Ursa Minor
18
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.

19
Ursa Major
20
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.

21
Draco
22
Orions Belt
22
23
Cassiopeia

• Cassiopeia was the beautiful wife of Cepheus,
  king of Ethiopia, and the mother of Andromeda.
  She is most famous in connection with the myth of
  her daughter, Andromeda. The queen made the
  mistake of bragging she was more lovely than the
  Nereids, or even than Juno herself. The goddesses
  were, needless to say, rather insulted, and went
  to Neptune, god of the sea, to complain. Neptune
  promptly sent a sea monster (possibly Cetus?) to
  ravage the coast. The king and queen were ordered
  to sacrifice their daughter to appease Neptune's
  wrath, and would have done so had Perseus not
  arrived to kill the monster in the nick of time.
  As a reward, the hero was wedded to the lovely
  Andromeda.

24
Cassiopeia
25
Cygnus

• Cygnus is a constellation in the northern sky.
  Its name means the swan in Latin, and it is
  most frequently associated with the myth of Zeus
  and Leda. The Swan constellation is easy to find
  in the sky as it features a well-known asterism
  known as the Northern Cross.
• Cygnus constellation is associated with several
  myths, most frequently the one of the Spartan
  Queen Leda, who gave birth to two sets of twins,
  the immortal Pollux and Helen and mortal Castor
  and Clytemnestra, after being seduced by the god
  Zeus, who had transformed himself into a swan.
  The immortal children were fathered by the god
  and the mortal ones by Ledas husband, King
  Tyndareus. Castor and Pollux are represented by
  the zodiac constellation Gemini.

26
Cygnus
27
Signs of the Zodiac

• Common Constellations

28
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.

29
Aquarius The Water Bearer
30
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.

31
Aries the Ram
32
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.

33
Cancer
34
Capricornus the Sea-Goat
The Sea Goat or Goat-Fish, as a creature with
the head and body of a goat and the tail of a
fish, may well have originated from
Assyro-Babylonian depictions of their god of
wisdom Oannes, who was half-man, half-fish.
35
Capricornus
36
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...)

37
(No Transcript)
38
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.

39
Leo
40
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.

41
Libra

42
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".)

43
Pisces
44
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.

45
Sagittarius
46
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.

47
Scorpius

48
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.

49
Taurus

50
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.

51
Virgo