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 Explain the conditions required for different types of lunar and solar eclipses.  Distinguish between different types of eclipses (partial, total, annular). 3 You should be able to:

4 I have A. Seen a lunar eclipse. B. Seen a solar eclipse. C. Seen both lunar and solar eclipses. D. Never seen an eclipse whatsoever.

5 Eclipses (solar + lunar combined) occur on average: A. About once every 3 months (about 4 per year) B. About once every year C. About once every 3 years D. About once every 5 years E. About once every 10 years

 Lunar eclipses: Moon in the Earth’s shadow.  Solar eclipses: Earth in the Moon’s shadow.  The Moon’s shadow falls on the Earth….  If you’re located in that shadow, the Moon is in front of [part of] the Sun! 6

7 A. New Moon B. First Quarter C. Full Moon D. Third Quarter E. None of the above Lunar eclipses happen at

8 From here (in the umbra), you cannot see the Sun at all. From here (in the penumbra), you can see part (but not all) of the Sun.

9 Not a single point on the Moon receives direct sunlight. Part of the Moon does not receive direct sunlight.

Moon slowly gets more and more covered by Earth’s shadow (umbra) Moon “completely” covered by Earth’s shadow (umbra). 10 A few hours from beginning to the end

 Starts with partial phase : bite out of the Sun that gets bigger…. 12

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Sun slowly gets more and more covered by the Moon Sun slowly gets less and less covered by the Moon While the Sun is completely covered, its faint thin atmosphere is visible

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Bailey’s beads 16

Diamond Ring 17

Corona 18

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Apparent sizes of Moon and Sun vary depends on distance from Earth

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27  The orbit of the Moon is slightly tilted with respect to the ecliptic.  Most of the time, the Moon is below or above the ecliptic plane -> no eclipse possible.  Crossing of the ecliptic plane happens at the nodes : ascending node and descending node  So eclipses only happen when the Moon is near a node AND the phase of the Moon is Full or New.

full moon (solar) OR new moon (lunar) AND Moon at or near one of two points in its orbit where it crosses ecliptic plane

29 Line of nodes keeps orientation in space! “Eclipse Seasons”

Coloured bands: 18 yr 11 1/3 d apart Saros cycle

Penumbral eclipses not listed. Typically 1-2 per year in this list. When two in a row : less Than 6 months apart ! 31

Typically 1-2 per year does not include partial eclipses When two in a row : less Than 6 months apart ! 32

 When Mercury or Venus is directly in front of the solar disk, there is a planetary transit  These are fairly rare : about 12 Mercury transits per century – next one May 9, 2016 Venus transits in pairs 8 years apart; pairs are separated by 105 years. Next one : June

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