Transcript Northern Circumpolar Constellations

Northern Circumpolar
Constellations
What does circumpolar mean?
• to circle around the pole- or North Star.
• daily trace circles around the north
celestial pole, without setting or dipping
below the horizon.
• move in a counterclockwise direction.
• On any given night, the constellation is
visible during a portion of the circle; the
rest is traced out when the constellation is
hidden in the daylight sky.
This is what I mean:
Circumpolar Constellations:
• Ursa Major, the Big Bear (includes the Big
Dipper)
• Ursa Minor, the Little Bear
• Cassiopeia, the Queen of Ethiopia
• Cepheus, the King of Ethiopia
• Draco the Dragon
The Big Dipper shows the way to
Polaris
But it is not a real constellation:
What is it? An ASTERISM
• The Big Dipper and Little Dipper are part
of two other official constellations
• The Great Bear and Little Bear
respectively.
• They are a familiar, but unofficial grouping
of stars.
The Little Dipper w/ Polaris
Why is Polaris so important?
•
it stays relatively fixed in the heavens while all
of the other stars move in circular arcs
throughout the night.
• In the past, it has been called ‘the ship star’, ‘the
leading star’, ‘star of the sea’ and the ‘steering
star’
• Native Americans called it the ‘nail of the sky’.
Draco the Dragon
The King and Queen
Does Precession effect the Pole
Star? YES!!
• The Earth is like a spinning top.
This wobble changes the spot that
the Earth’s axis points to in the
Northern sky.
These are the stars visible in the southern polar sky.