observing the moon and eclipses
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Observing the Moon and Eclipses. Astronomy 311 Professor Lee Carkner Lecture 4. What were the most important contributions to planetary science of Tycho, Kepler, and Galileo respectively?. - PowerPoint PPT PresentationTRANSCRIPT
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Observing the Moon and Eclipses
Astronomy 311Professor Lee
CarknerLecture 4
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What were the most important contributions to planetary science of Tycho, Kepler, and Galileo respectively?
a) Observing with a telescope, Determining the laws of planetary motion, Measuring the motions of the planets
b) Determining the laws of planetary motion, Observing with a telescope, Measuring the motions of the planets,
c) Observing with a telescope, Measuring the motions of the planets, Determining the laws of planetary motion
d) Measuring the motions of the planets, Determining the laws of planetary motion, Observing with a telescope
e) Measuring the motions of the planets, Observing with a telescope, Determining the laws of planetary motion
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What period in history saw the greatest increase in our understanding of the physical properties of the solar system?a) 200 BC – 200 ADb) 1550 AD -1650 ADc) 1650 AD – 1800 ADd) 1900 AD – 1950 ADe) 1950 AD – 2000 AD
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Moon Basics
Shows 1 complete set of phases in one month
Phase is determined by how much of
the lit side we can see
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New --
Quarter -- see 1/2 illuminated side
Full --
Crescent --
Gibbous -- more than 1/2 of illuminated side
Waxing --
Waning -- decreasing brightness
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Sidereal and Synodic Sidereal period -- time for moon to
return to initial position with respect to the stars (27.3 days)
Synodic period -- time for moon to return to initial position with respect to the sun (29.5 days)
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Why is a Synodic Month Longer than a Sidereal
Month?
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Where is the Moon? Since the moon makes one orbit in
about 30 days, it moves 1/30 of a complete circle in the sky in one day
Moon is ~12 degrees further east
each night
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Eclipses Solar Eclipse
Happens during New moon Lunar Eclipse
Happens during Full moon
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When do Eclipses Happen?
Moon’s orbit is tilted by about 5 degrees with respect to the ecliptic (plane of the Sun and Earth)
Only have eclipses when Sun falls on line of nodes (line where the orbital plane of the Earth and Moon intersect)
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Line of Nodes
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Shadows on the Moon Umbra -- Darkest part of the shadow
Penumbra -- Less dark part of shadow,
region is still getting some sunlight
Penumbral eclipses can be hard to notice
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Geometry of a Lunar Eclipse
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Types of Lunar Eclipses Total Eclipse -- Moon is completely covered
Partial -- Moon is partially covered
Penumbral --
You can still faintly see the Moon even during a total lunar eclipse because of scattered light (circular sunset)
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Lunar Eclipse
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Types of Solar Eclipses Total Eclipse -- Sun is completely
covered
Partial -- Sun is partially covered
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Annular Eclipse Moon is about 400 times smaller than
the Sun, but is also about 400 times closer
When the Moon is the furthest from the Earth it does not completely cover the Sun
Annular Eclipse --
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Annular Eclipse
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Solar Eclipse from Space
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Next Eclipses Eclipses visible from central U.S.
Lunar – Total solar eclipse – August 21, 2017
For any given location, you see many more lunar than solar eclipses
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Next Time Read chapter 2.5-2.8 for next time
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Summary Orbit
one complete orbit in one sidereal month
same side always faces the Earth Phases
complete set in one synodic month where the Moon is in sky at a
particular time depends on the phase
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Eclipses caused by Earth or Moon blocking out
the Sun only occur when line of nodes points
at Sun are darkest when in the umbra occur in cycles