Constellations

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Constellations
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Patterns of Stars
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.
A pattern or group of stars in the sky is called
a constellation.
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Orion
When the gods were tired of him, the sent a
scorpion to bite and kill him.
Orion is one of the brightest constellations and
is a mythological character.
According to Greek myths, Orion was a hunter who
used to brag all the time. This bother the gods.
The gods felt bad for doing having Orion killed,
they they placed him in the sky.
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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
  Earths north pole each night. These stars are
  called circumpolar.

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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.

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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.

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Interesting Facts
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 3.158 of the sky.
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Quick Review
1. What is a constellation?
2. Why is Polaris called the North Star?
3. How did ancient people use the seasonal
appearance of certain constellations?
4. Name two constellations.