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Earth Motions and the Heavens

Earth Motions and the Heavens. Rotation Revolution Precession. What are the basic Earth motions?. Rotation. Revolution. Precession. http://www.snyder7hills.org/units/ss/ch1/rotrev.html. What are the apparent celestial motions associated with Earth’s rotation?.

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Earth Motions and the Heavens

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  1. Earth Motions and the Heavens Rotation Revolution Precession

  2. What are the basic Earth motions? Rotation Revolution Precession http://www.snyder7hills.org/units/ss/ch1/rotrev.html

  3. What are the apparent celestial motions associated with Earth’s rotation? http://en.wikipedia.org/wiki/File:AxialTiltObliquity.png

  4. http://3.bp.blogspot.com/-hlq7nqAtZlk/Tt5F-HTu6WI/AAAAAAAADEE/ukVSOFugs2w/s1600/startrails.jpghttp://3.bp.blogspot.com/-hlq7nqAtZlk/Tt5F-HTu6WI/AAAAAAAADEE/ukVSOFugs2w/s1600/startrails.jpg

  5. What are Star Trails? http://zuserver2.star.ucl.ac.uk/~idh/apod/image/0609/gemstartrails_schulz_f.jpg

  6. What is the apparent hourly rate of motion of the stars? • Stars appear to move 15°/hrbecausethe Earth rotates at 15°/hr.

  7. Star trails over the 60 inch dome at Palomar Observatory

  8. 3 hour view of night at Palomar http://www.astro.caltech.edu/palomar/images/star.trails.jpg

  9. How do star trails change with direction? • North- circumpolar • East- rising • South- arc from east to west • West- setting

  10. http://www.astro.caltech.edu/palomar/images/haletrails.jpg

  11. Looking out the window… East North West South

  12. Star positions change throughout the night (except for Polaris) because the Earth rotates

  13. A view of the GEMINI North dome on Mona Kea soon after sunset showing star trails from a time-lapse exposure. Also seen are trails from vehicle headlights as they drive passed the GEMINI dome. http://gemini.physics.ox.ac.uk/photos/gemini-trails-mr.gif

  14. Lecture Tutorial: Position

  15. Position You observe a star rising due east. When this star reaches its highest position above the horizon, where will it be? a) high in the northern sky b) high in the eastern sky c) high in the southern sky d) high in the western sky e) directly overhead

  16. Imagine you are standing in the northern hemisphere. Looking directly north, you see a star just above the horizon. A little later you notice that it has shifted position slightly. Which way did it move? a) to the right, (east) b) to the left, (west) c) up, (rising) d) down, (setting)

  17. Lecture Tutorial: Motion

  18. Motion

  19. Motion

  20. How much of the celestial sphere can an Earth observer see at one time? a) less than half b) exactly half c) more than half Review Lecture Tutorial

  21. Celestial Sphere: Geocentric View

  22. How is Polaris different from other stars? • Polaris doesn’t appear to move (much) because it aligns with the spin axis (within about 1 degree). • Polaris’ position is North, stationary, and its altitude is equal to the observer’s latitude

  23. The stars positions change throughout the night (except for Polaris) because the Earth rotates and Polaris aligns with the spin axis.

  24. What is special about Circumpolar Stars? • Circle counterclockwise around Polaris • Never rise or set during the night • Visible all year

  25. Orion Why does Orion look different in the Southern Hemisphere?

  26. http://www.dimijianimages.com/Africa-p10/star-trails-south-TX-gallery.jpghttp://www.dimijianimages.com/Africa-p10/star-trails-south-TX-gallery.jpg

  27. Orion in Southern Hemisphere Sirius is blue Betelgeuse is red http://www.starrynightphotos.com/star_trails/images/star_trails_orion.jpg

  28. What is the affect of latitude on star trails? • Near the equator, stars in the eastern sky trail directly up and over your head. • At higher latitude stars are tilted with respect to the rotating "sphere" of the sky. • At either pole the stars would go around the horizon.

  29. http://ganymede.nmsu.edu/tharriso/ast110/class05.html

  30. http://images.google.com/imgres?imgurl=http://www.dimijianimages.com/Africa-p10/star-trails-south-TX-gallery.jpg&imgrefurl=http://www.dimijianimages.com/Africa-p10/star-trails-south-TX.htm&usg=__Ko6DW_HfnHz6RuO4benYIjBf914=&h=592&w=850&sz=167&hl=en&start=54&um=1&itbs=1&tbnid=x7Kg-doC9kpKAM:&tbnh=101&tbnw=145&prev=/images%3Fq%3DSTAR%2BTRAILS%26start%3D40%26um%3D1%26hl%3Den%26safe%3Dactive%26sa%3DN%26rls%3Dcom.microsoft:en-us%26ndsp%3D20%26tbs%3Disch:1http://images.google.com/imgres?imgurl=http://www.dimijianimages.com/Africa-p10/star-trails-south-TX-gallery.jpg&imgrefurl=http://www.dimijianimages.com/Africa-p10/star-trails-south-TX.htm&usg=__Ko6DW_HfnHz6RuO4benYIjBf914=&h=592&w=850&sz=167&hl=en&start=54&um=1&itbs=1&tbnid=x7Kg-doC9kpKAM:&tbnh=101&tbnw=145&prev=/images%3Fq%3DSTAR%2BTRAILS%26start%3D40%26um%3D1%26hl%3Den%26safe%3Dactive%26sa%3DN%26rls%3Dcom.microsoft:en-us%26ndsp%3D20%26tbs%3Disch:1 View East at Equator

  31. South Pole This is another picture of the South Pole, but shorter. Two nearby galaxies are visible in this image. The large fuzzy one, just above the roof of the Commons Building, is the Large Magellanic Cloud, and the smaller fuzzy patch near the top of the image is the Small Magellanic Cloud. These galaxies are 200,000 light years away, yet easily visible to the naked eye in dark skies!

  32. Lecture tutorial: Seasonal Stars

  33. Intro You go out tonight and see the brightest star in the constellation Orion just rising above your eastern horizon at 10 PM. One week later at 10 PM this same star will be a) slightly higher in the sky. b) at the same height as before. c) below your horizon. d) setting on your western horizon.

  34. Lecture tutorial: Seasonal Stars

  35. What is the affect of Earth’s Revolution on the sky? http://bigbendnow.com/wp-content/uploads/2012/06/Night-Sky-Changes-with-the-Seasons.jpg

  36. http://ganymede.nmsu.edu/tharriso/ast110/ch02f14.0_0.jpg

  37. What is the affect of Earth’s Revolution on the night sky? Earth motion is counterclockwise in this picture Night stars will appear to have shifted to the west- Meaning they have risen earlier

  38. How far do stars shift from night to night? • Earth revolves around Sun 360° in one year • So in 12 months Earth moves 360°, so the stars appear to shift 30° to the west • And in one day, Earth moves 1°, so the stars appear to shift 1° to the west

  39. How does Earth’s revolution affect the times of star rising and setting? • Stars appear to rise earlier every night 24 hours x 60 minutes = 1440 minutes per day day hours 1440 minutes/day = 4 minutes 360°/day • Stars rise 4 minutes earlier each day

  40. What is the ecliptic? http://www.eso.org/public/outreach/eduoff/vt-2004/Background/Infol2/vt2004-if11-fig2.jpg

  41. http://www.calendrier-lunaire.fr/en_US/eclipses-de-lune-et-de-soleil-comprendre-le-calendrier-lunaire.htmlhttp://www.calendrier-lunaire.fr/en_US/eclipses-de-lune-et-de-soleil-comprendre-le-calendrier-lunaire.html

  42. http://www.calendrier-lunaire.fr/uploads/images/Anglais/UNDERSTANDING/eclipse.jpghttp://www.calendrier-lunaire.fr/uploads/images/Anglais/UNDERSTANDING/eclipse.jpg

  43. http://star.wind.mystarband.net/bib/images/moon_orbital_phases.gifhttp://star.wind.mystarband.net/bib/images/moon_orbital_phases.gif

  44. http://lcogt.net/files/styles/fourcol-image/public/spacebook/Ecliptic%20repair.pnghttp://lcogt.net/files/styles/fourcol-image/public/spacebook/Ecliptic%20repair.png

  45. Ecliptic is the plane of the solar system- where we find the planets and the Sun http://cse.ssl.berkeley.edu/img/eclip.gif

  46. http://physics.uoregon.edu/~jimbrau/BrauImNew/Chap06/FG06_05.jpghttp://physics.uoregon.edu/~jimbrau/BrauImNew/Chap06/FG06_05.jpg

  47. What can we see on the Ecliptic? http://ganymede.nmsu.edu/tharriso/ast110/class05.html

  48. http://upload.wikimedia.org/wikipedia/commons/b/bd/Earths_orbit_and_ecliptic.PNGhttp://upload.wikimedia.org/wikipedia/commons/b/bd/Earths_orbit_and_ecliptic.PNG

  49. How is the Ecliptic related to the seasons? When the sun is crosses the celestial equator, we have the first day of spring or fall. http://i131.photobucket.com/albums/p301/glactus/space%20album%20three/ecliptic310x272.jpg

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