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 Cassiopeia Cepheus Draco , the Little Bear , the Queen of Ethiopia , the King of Ethiopia 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.