Solar Eclipse

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Lunar and Solar Eclipses ("Synodic Blackouts") a) General Introduction to Eclipses Eclipses may occur when the Sun, Moon, and Earth line up in a straight line, with either the Moon or the Earth in the middle. If they line up exactly, then one body (whichever is not in the middle) will be shadowed or eclipsed by the other. Consider these questions and then read the descriptions of solar and lunar eclipses:

  1. At which phase(s) of the Lunar Cycle are the Sun, Moon, and Earth lined up, in any order, on a straight line?
  2. Which body is eclipsed for a lunar eclipse?
  3. Which body is eclipsed for a solar eclipse?
  4. Which body is in the middle for a lunar eclipse? For a solar eclipse?
  5. Why would an eclipse not happen every time there is a Full or New Moon?
  6. Draw and label three circles Sun, Earth and Moon so that their alignment corresponds to that occurring at a solar eclipse. Show how the appropriate body is eclipsed.
  7. During a solar eclipse, in which phase is the Moon?
  8. Draw and label three circles Sun, Earth and Moon so that their alignment corresponds to that occurring at a lunar eclipse. Show how the appropriate body is eclipsed.
  9. During a lunar eclipse, in which phase is the Moon?
  10. Why does an eclipse not occur at every Full Moon or New Moon? Anatomy of a Lunar Eclipse The Moon is obscured by shadow of the Earth (at that distance, the Earth's shadow cone is about 3 times the Moon's diameter). The angular diameter of the Moon is about half a degree. Angle Sun&endash;Earth&endash;Moon = 180degrees (opposition of Moon and Sun). Occurs only at Full Moon. Does not occur at every Full Moon. Visible from most of the Earth. Anatomy of a Solar Eclipse. Earth touched by shadow of the Moon (Sun obscured by disk of Moon) --at that distance, the tip of the Moon's shadow cone only just reaches the Earth. The angular diameter of the Sun = Moon = 1/2 degrees. Angle Sun&endash;Moon&endash;Earth = 0degrees (conjunction of Moon and Sun) Occurs only at New Moon. Does not occur at every New Moon. Visible only from certain latitudes of the Earth; not from the entire globe.
  11. Draw and label three circles Sun, Earth and Moon so that their alignment corresponds to that occurring at a solar eclipse. Show how the appropriate body is eclipsed.
  12. During a solar eclipse, in which phase is the Moon?
  13. Draw and label three circles Sun, Earth and Moon so that their alignment corresponds to that occurring at a lunar eclipse. Show how the appropriate body is eclipsed.
  14. During a lunar eclipse, in which phase is the Moon?
  15. Why does an eclipse not occur at every Full Moon or New Moon?
  16. The visibility of which eclipse would be harder to predict, solar or lunar? Explain why.
  17. See Crowe, p. 8, problem #5; pp. 10&endash;15, problems #7, 8, & 9.

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