Transcript PPT

Constellations
A pattern or
group of stars
in the sky is
called a
constellation.
People of ancient
time saw the
constellations as
character or animals
in the sky. They
made up stories to
explain how the
object, animal, or
character came into
the night sky.
Orion
Orion is one
of the
brightest
constellation
s and is a
mythological
character.
According to
Greek myths,
Orion was a
hunter who
used to brag
all the time.
This bother
the gods.
When the gods
were tired of
him, the sent
a scorpion to
bite and kill
him.
The gods felt
bad for doing
having Orion
killed, they
they placed him
in the sky.
Stars as Tools for Navigation
 Earth rotates on its axis, this makes most
constellations appear to rise in the east and
set in the west during the night.
 Most constellations appear in many
different positions in the sky as the Earth
revolves around the sun.
 There is a group of stars that appear in the sky all
night long and all year long. It seems that these stars
do not rise and set, but circle the Earth’s north pole
each night. These stars are called circumpolar.
Stars as Tools for Navigation
 The North Star is called Polaris and located directly
above the North Pole. This star appears in the same
place every night all year long.
 In the Northern Hemisphere, if you find Polaris you
will be able to tell which direction is north.
The Southern Hemisphere does not have a star to help
you find its pole. In stead it has what is known as a
Southern Cross.
 The Southern Cross consists of 4 bright stars and
some dimmer ones. All of these together point to the
south pole.
Stars As Calendars
 It seems that the constellations in the east rise a
little earlier each evening. This means that the
seasons are changing and we are seeing different
constellations.
 An example is in the Northern Hemisphere, Orion is
high in the sky during the winter and Scorpio can only
be seen during the summer.
 People of ancient times used these seasonal changes
in the stars as calendars.
 It is believed that the ancient people used the
constellations to tell them when to plant and harvest
crops. An example would be Leo and Virgo in the night
sky would signify that the last frosts of the year
have happened and it is safe to plant. This worked
much like our paper calendars work for us today.
•The brightest constellation is Crux (the
Southern Cross).
•The constellation with the greatest
number of visible stars in it is Centaurus
(the Centaur - with 101 stars). The
largest constellation is Hydra (The Water
Snake) which extends over 3.2% of the sky.
Ursa Major
Ursa Major
• Ursa Major, the Great Bear, is visible in
the Northern Hemisphere all year long.
• Ursa Major is the best known of the
constellation and it appears in every
reference known.
• The story behind it:
– Callisto was changed to a bear because of
Zeus's jealousy and transferred her to the sky.
This is improbable, as the constellation was
already well established before this time. The
drawings all show a bear with a long tail,
again not likely correct since bears have no
tails. The most likely explanation for the
bears is the fact that Native Americans called
the constellations the bear, but instead of the
tail they depict the bear being chased around
the pole by seven braves.
Ursa Minor
Circumpolar Constellation
Ursa Minor
• Ursa Minor, the Little Bear, is
visible in the Northern Hemisphere
all year long.
• Ursa Minor is mostly known for
Polaris, the North Star which may be
found at the end of the handle.
• The story behind it:
– Ursa Minor does not have any mythology
attached to it, it was created in the
6th century B.C. as a navigational aid
for sailors out of a long forgotten
constellation called the Dragon's wing.
Cepheus
Cepheus
• The story behind it:
– Cepheus was the King of Ethiopia. He married Cassiopeia
and they had a daughter Andromeda. Cassiopeia was
incredibly beautiful but immensely vain. She was also
proud of her daughter's beauty. In fact she continually
boasted that the two of them were more beautiful than any
of the fifty sea nymphs who attended Poseidon's court.
– These nymphs (the Nereids) complained to Poseidon, who
felt he had to defend his own reputation. So he sent a
flood to devastate Cepheus' kingdom. The oracles told
Cepheus that in order to save his people he must sacrifice
his daughter to a great sea monster: Andromeda was tied to
a rock along the coastline, dressed only in her jewelry.
The monster would be along in due time to take his prize.
– At that moment Perseus came flying by. He had just killed
the Gorgon Medusa and was carrying the severed head back
to Athene. To make a long story short, he saved her then
turned everyone into stone by showing them the severed
head.
– Poseidon then put the stone frozen Cepheus and Cassiopeia
into the heavens, but with a twist: he made the vain
Cassiopeia spin around on her chair, spending half the
year upside down. As for Cepheus, Poseidon gave him a
number of medium sized stars that go to make his square
face with a pointed crown.
Cassiopeia
Cassiopeia
• This constellation is at the edge of
the Milky Way galaxy and has the shape
of a "W".
• The story behind it:
– Cassiopeia had been the wife of Cepheus.
Because she thought herself more beautiful
than the daughters of Nereus, a god of the
sea, she angered the god Poseidon. To punish
her, her daughter was chained to a rock of
the coast as a sacrifice for a sea monster.
Andromeda was saved from death by Perseus.
To learn humility Cassiopeia was banned to
the sky hanging half of the time head
downward.
Draco
• Draco, the Dragon, used
to hold special
significance as the
location of the pole
star, but due to the
Earth's precession, the
pole has shifted to
Polaris in Ursa Minor.
• The story behind it:
– The dragon is Ladon,
the guardian of the
'golden apples' of
immortality which grew
in the garden of
Hesperides, beyond the
River of Time, in the
land of death. It is
Ladon which Hercules
kills in his 11th
labor to get the
golden apples.
Circumpolar Constellations
Orion
•
•
•
Orion is the master of the winter skies. He lords over the
heavens from late fall to early spring, with his hunting dog
Sirius trailing at his feet.
The story behind it: (Orion holding a bow)
– Orion was a handsome and famous hunter. The Battle-Goddess
Anat fell in love with him, but when he refused to lend her
his bow, she sent another man to steal it. This chap
bungled the job, and wound up killing Orion and dropping
the bow into the sea. This is said to explain the
astronomical fact that Orion and the Bow (an older version
of the constellation) drops below the horizon for two
months every spring.
Another story behind it: (Orion holding an animal)
– Orion was known as the "dweller of the mountain", and was
famous for his prowess both as a hunter and as a lover. But
when he boasted that he would eventually rid the earth of
all the wild animals, his doom may have been sealed. The
Earth Goddess sent the deadly scorpion to Orion to kill
him. Orion engaged the scorpion in battle but quickly
realized its amour was impervious to any mortal's attack.
Orion then jumped into the sea and died. In his eternal
hunting, Orion is careful to keep well ahead of the
scorpion. Orion has disappears over the horizon by the time
Scorpio rises in the east, as it becomes his turn to rule
the evening sky.
Orion
Not a circumpolar constellation, but a
seasonal constellation
Betelgeuse, the right arm of Orion (or "armpit" as the
name suggests), glows with a dull red.
Rigel, in the opposite corner of the constellation, is
much brighter.
• Orion
•On the left: The Hunter - Orion
•In the middle: Name: The Bull - Taurus
•On the right: Name: The Greater Dog - Canis Major
• On the left: The Lion - Leo
– There is a record of the Lion in an astronomical
poem from Greece in the 3rd or 4th century B.C.
• In the middle: The Herdsman - Böötes
• On the right: The Virgin - Virgo
– At first, this constellation was recognized as
the figure of a stalk of wheat, and then was
introduced to the Greeks and become the figure
of a virgin who holds a stalk of wheat, linking
it with Greek mythology and legend.
• On the left: The Crab - Cancer
– Its name is Cancer in Latin, which is the same name as the
disease, cancer. This disease was named after the shell of
the crab, which is similar to the shape of breast cancer.
• In the middle: The Scorpion - Scorpio
– The Scorpion has existed since the oldest of times. After
sunset, around the 7th of July, you can see it in the shape
of a large S above the southern horizon where the milky way
is streaming down. The figure of this constellation was
originally the figure of a scorpion with scissors. Later the
scissors were separated to become the Balance.
• On the right: The Archer - Sagittarius
– The Archer has been recognized since the Babylonian era. At
that time it was the figure of a man with a bow in his hand,
not the present figure of the half man half horse which is
recognized in Greek mythology.
• On the left and in the middle: Andromeda
– The Andromeda constellation is famous for
containing the Andromeda Nebula, the closest
galaxy to our Milky Way. Andromeda was chained
up for a sea monster to devour her.
– Andromeda is also the daughter of Cassiopeia &
Cepheus
• On the right: The Fishes, Pisces
– In ancient Babylon, this constellation was
viewed as the figure of a mermaid tied together
with a swallow with a fish tail. The present
figure appeared in a 3rd or 4th century B.C.
Greek poem.
Signs
Of The
Zodiac
From our
perspective on
earth, the sun
takes a path
through the sky
(known as the
ecliptic). It
passes through
these
constellations.
Ecliptic Constellations
& Zodiac Signs
• A band of 12 constellations
around the sky entered on the
ecliptic (apparent path of the
sun on the earth as the earth
revolves around it).
• Aries, Leo, Sagittarius, Taurus,
Virgo, Capricorn, Gemini, Libra,
Aquarius, Cancer, Scorpio, and
Pisces.
Ecliptic Constellations
Andromeda
Antlia
Apus
Aquarius
Aquila
Ara
Aries
Auriga
Boötes
Caelum
Camelopardalis
Cancer
Canes Venatici
Canis Major
Canis Minor
Capricornus
Carina
Cassiopeia
Centaurus
Cepheus
Cetus
Chamaeleon
Circinus
Columba
Coma Berenices
Corona Australis
Corona Borealis
Corvus
Crater
Crux
Cygnus
Delphinus
Dorado
Draco
Equuleus
Eridanus
Fornax
Gemini
Grus
Hercules
Horologium
Hydra
Hydrus
Indus
Lacerta
Leo
Leo Minor
Lepus
Libra
Lupus
Lynx
Lyra
Mensa
Microscopium
Monoceros
Musca
Norma
Octans
Ophiuchus
Orion
Pavo
Pegasus
Perseus
Phoenix
Pictor
Pisces
Piscis Austrinus
Puppis
Pyxis
Reticulum
Sagitta
Sagittarius
Scorpius
Sculptor
Scutum
Serpens
Sextans
Taurus
Telescopium
Triangulum
Triangulum Australe
Tucana
Ursa Major
Ursa Minor
Vela
Virgo
Volans
Vulpecula