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GE 150 Astronomy

GE 150 Astronomy. Week #4 February 5 ,7 2013. Lunar Phases II. Rising/Setting/Visibility of Lunar Phases. Moonrise and Moonset during Full Moon:. Full Moon rises as the Sun sets. The Full Moon is high in south at Midnight. Full Moon sets as the Sun rises.

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GE 150 Astronomy

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  1. GE 150 Astronomy Week #4 February 5,7 2013

  2. Lunar Phases II

  3. Rising/Setting/Visibility of Lunar Phases

  4. Moonrise and Moonset during Full Moon: • Full Moon rises as the Sun sets. • The Full Moon is high in south at Midnight. • Full Moon sets as the Sun rises. • Full Moon cannot be seen during the day.

  5. Moonrise, Moonset... • Not all Moon phases are visible at all times of the day • Never see a Full Moon during the day • Never see a Crescent Moon at midnight. • Never see the Last Quarter Moon at sunset. • Rising/setting times depend on the details of the Earth-Sun-Moon configuration as viewed from the surface of the rotating Earth.

  6. Phases of the Moon East What time is it when the waxing crescent moon is highest in the sky? When does it first rise? When does it set? West

  7. Phases of the Moon What time is it when the waxing crescent moon is highest in the sky? When does it first rise? When does it set? East West

  8. Phases of the Moon West What time is it when the waxing crescent moon is highest in the sky? When does it first rise? When does it set? East

  9. Phases of the Moon East What moon phase would be rising in the East at 3pm? What Moon phase would be setting in the West at 3pm? West

  10. Phases of the Moon If the Moon is highest in the sky at 9pm today, What phase will the Moon be in three weeks from today?

  11. In each phase of the Moon, how much of the Moon’s total surface is lit by the Sun? Half the Moon is always lit by the Sun Except . . .

  12. Eclipses

  13. Solar Eclipses • Sometimes at New Moon, the alignment is just right, allowing the Moon to block the light from the Sun, creating an eclipse

  14. Annular Eclipse Partial Eclipse Total Eclipse Solar Eclipse

  15. Solar Eclipse – the Shadow of the Moon

  16. Solar Eclipses • Path of July 1991 eclipse as seen by the GOES weather satellites (time lapse)

  17. Lunar Eclipse – the Shadow of the Earth

  18. Lunar Eclipse – the Shadow of the Earth • The reddish glow is from light refracted through the Earth’s atmosphere and reflected back to Earth (think sunset)

  19. Lunar Eclipses

  20. Lunar Eclipses Time

  21. Lunar Eclipses Sunlight refracted and filtered through the Earth’s atmosphere Lunar eclipse viewed from the Moon (artist conception)

  22. Why Doesn’t an Eclipse Happen Every Full/New Moon Ecliptic – name derives from “Eclipse Line” “Line of Nodes” – point where the two orbits cross, has to be pointed toward the Sun Moon’s orbit is tilted 5 degrees with respect to the Earth’s orbit Eclipses occur ONLY when the Moon CROSSES the plane of Earth’s orbit around the Sun AND ONLY during the NEW or FULL phases

  23. Everything Must Align Just Right • Moon must be crossing the Earth’s orbit (ecliptic) at the same time it passes either in front of (New Phase; solar eclipse) or behind (Full Phase; lunar eclipse) the Earth • Nodes aligned: Eclipse at B & D • No alignment therefore no Eclipse at A & C, just normal phases

  24. Which positions cause which eclipses • When the ______ is in the _____ phase and is directly in line with the _____ and the ____, you get a ______ eclipse. • When the ______ is in the _____ phase and is directly in line with the _____ and the ____, you get a ______ eclipse.

  25. Using Star Charts

  26. Consider the dome of the sky over our heads…. mixing bowl

  27. Consider the dome of the sky over our heads…. inverted mixing bowl ….

  28. The Sky Tonight at 7 PM Generated from Astroviewer.com North Star- “Polaris” Zenith Horizon Partial Meridian

  29. Use the winter triangle to find constellations during winter evenings

  30. Use the Summer Triangle to find constellations during summer evenings

  31. Anyone recognize any shapes here?

  32. Pleiades Great Orion Nebula Using Orion in to find other objects Betelgeuse Aldebaran Rigel SIRIUS

  33. Pleiades Seven Sisters Subaru

  34. Orion Nebula

  35. Using the Big Dipper in the northern sky as a way to find other groups of stars

  36. How to find stuff in the sky – Star Charts • http://skymaps.com/ • Free PDF monthly sky maps – with nightly guide • http://www.fourmilab.ch/yoursky/ • Interactive star map with man options/features • http://www.astro.wisc.edu/~dolan/constellations/constellationjavalist.html • Interactive view of individual constellations

  37. Other Strange Facts about the Moon

  38. Why does the same side always points toward Earth? • Rotation period = orbital period • Tidal locking

  39. Tidal Locking of the Moon

  40. Lunar Phases October 2007 • Moon “wobbles” – Libration • 59% of the surface

  41. Zodiac Signs Then and Now

  42. Precession Cause: Sun’s gravity tugs a little on the Earth’s rotation axis as Earth goes around the Sun Precession takes 26,000 years to complete one cycle

  43. Precession

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