Constellations pg. 617

1. Constellations pg. 617 # of stars? Patterns Definition of Constellation Uses? How many Constellations? Names Asterisms

2. There are about 6000 named, visible stars in the sky.

3. Astronomy: the oldest science! Aristotelian view Has the earth and sky on fixed spheres • The ancients imagined that the Earth was surrounded by a canopy of stars

4. The Celestial Sphere:a globe of the sky! An imaginary bubble that surrounds Earth onto which all the stars are positioned. Like Earth, the Celestial sphere has a “North Pole”, a “South Pole”, and an equator.

5. The Celestial sphere seems to be tipped over. It is actually Earth that is at an angle (tipped over at an angle of 23.5° Ecliptic: the path of the sunthrough the sky

6. Celestial Portraits • Human brains naturally create patterns. • What do you see when you look at the clouds? • The ancients did the same when they looked up at the sky.

7. Do you see a pattern in these stars?

8. Constellations • A name given to a group of stars • Named after heroes, animals, monsters, objects. • A human invention (not a natural grouping) http://www.videojug.com/film/what-is-a-constellation http://www.youtube.com/watch?v=QXeEAQtC75g

9. Constellations pg. 714 • 88 constellations in all • We still use 48 of the ancient ones and have added 40 new ones • 28 are in the northern sky, 48 are in the southern, • The 12 are the zodiac constellations • In the Northern Hemisphere their named for mythology • In the Southern Hemisphere they have modern names

10. Asterisms • A named group of stars that is part of a larger constellation • Example • The Big Dipper is part of the larger constellation Ursa Major

11. The “tea pot” asterism in the constellation Sagittarius

12. The Big Bear Can you find the stars of the Big Dipper in the constellation?

13. Tell a story • Orion was a mythical hero and hunter, and in his amorous pursuit of the Pleiades (the 7 daughters of the giant Atlas), the Gods placed them in the sky. And Orion chases after them in the sky for all eternity.

14. Your Turn! • Using a photo of the stars in the night sky, • Look for a pattern, picture, figure, of an object, person, by connecting the stars. • Outline the figure in a colored pencil. • Name the constellation • Create a mythological story to go with your constellation

15. We see a “flat” image of the stars in the constellations, but the stars are actually located at varying distances form earth.

16. To locate a place on the surface of the earth we use coordinates.What is the location of Chicago? Shuffle the deck and have sum fun

17. DEC (declination)is similar to latitude on Earth. DEC is measured from the celestial equator in degrees. Measurement to the NORTH is positive. The celestial North Pole is at +90 degrees DEC. Measurement to the South is negative. The South Celestial Pole is at _______degrees DEC -90

18. RA(right ascension) is measured in hours, minutes, and seconds, as if we were measuring time instead of position! 0-24 hrs RA reads to the EAST. Astronomers decided to begin RA at the point where the path of the ecliptic crosses the celestial equator: the first day of SPRING. (vernal equinox)

19. Stars, constellations, planets, can be found using the coordinates of declination and right ascension on the celestial sphere. Locate Cygnus the Swan (looks like a cross)

20. Zodiac Constellations The 12 constellations that the Sun move through during the year.

21. Circumpolar Constellations

22. Ursa Minor: Little Dipper The last star in the handle of the Little Dipper is the North Star: Polaris http://www.youtube.com/watch?v=N93WV61ETo8

23. Precession: The Earth is not a perfect circle so it does not have a perfect rotational spin. It “wobbles” like a top. So Polaris has not always been the “North” Star.

24. Cassiopeia

25. Draco the Dragon

26. Corona Borealis The Northern Crown