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52 Cards in this Set
- Front
- Back
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The seasonal shifting of a nearby star's position relative to more distant objects.
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Parallax
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The average distance between the Earth and the Sun (=1.5 x 10eight km)
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astronomical unit
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The distance light travels in one year.
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Light-year (=9.46 x 10twelve km)
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A distance measure determined by the shifting of a star against the background sky every 6 months (=3.26 ly)
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parasec
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A small and dim but hot star.
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White dwarf
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A large and bright but cool star
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red giant
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A method of finding a star's distance from its absolute magnitude and spectral type of color.
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spectroscopic parallax
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The science of measuring the apparent magnitudes of stars by imaging them through different filters
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photometry
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A two-filter measure of the color, and hence temperature of a star.
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Color-index
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A logarithmically scaled value for the MEASURED brightness of a star
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apparent magnitude
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The apparent magnitude verses spectral type.
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absolute magnitude
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A plot of star absolute magnitude versus spectral type.
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H-R diagram
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The line on an H-R diagram going from upper left to lower right where normal stars of different masses reside.
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main sequence
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The greek philosopher responsible for making stellar magnitude scale.
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Hipparchus
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The relation that tells how light dims with distance
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Inverse square law
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A continuous spectrum of light missing energy at a few wave lengths.
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absorption spectrum
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The act of removing an electron from an atom
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Ionization
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The law stating that otter blackbodies look bluer than cooler blackbodies.
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Wien's law
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All possible types of energy that can be emitted and absorbed by atoms.
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electromagnetic radiation
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A perfect absorber and radiator of electromagnetic radiation.
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blackbody
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Velocity or motion away from us, along our line of sight.
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radial velocity
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The number of protons in an atom.
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atomic number
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A spread of light with an uninterrupted wavelength distribution of energy.
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continuous spectrum
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The wavelengths where a specific element can absorb or emit light
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spectral lines
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The law that describes the blackbody curve, and led to quantum mechanics.
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planck's law
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The location around an atom where an electron resides.
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energy level
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The science of measuring light energy by wavelength.
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spectroscopy
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A spectrum of light with energy at only a few wavelengths.
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emission spectrum
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A subatomic particle with a negative charge. It creates light.
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electron
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The law that says light energy from a blackbody increases as (temperature)4.
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Stephen-Boltzman law
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A particle of light
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Photon
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The lowest energy level of an atom.
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ground state
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The laws that predict the possible types of spectra.
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Kirchhoffs' law
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All wavelengths of light emitted by a blackbody.
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blackbody curve
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The imaginary sphere centered on the Earth that holds the stars.
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celestial sphere
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The projection of the Earth's equator onto the celestial sphere.
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celestial equator
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The point directly overhead.
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zenith
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The north-south line passing directly overhead through the zenith.
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meridian
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When the Sun is farthest north of the celestial equator (about June 22)
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summer solstice
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When the Sun moves from north to south across the celestial equator (about September 23).
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autumnal equinox
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When the Sun is farthest south of the celestial equator (about December 22).
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winter solstice
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When the Sun moves from south to north across the celestial equator (about March 21).
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vernal equinox
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The apparent path of the Sun through the stars on the celestial sphere.
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ecliptic
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The place in the sky that the Earth's axis points toward (can be either north or south).
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celestial pole
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The slow wobble of the Earth on its rotation axis.
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Precession
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The rotation period of the Earth measured relative to the Sun.
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synodic day
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The rotation period of the Earth measured relative to the stars.
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sideral day
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When the Moon entirely blocks the Sun
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total eclipse
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An eclipse of the Sun that occurs when the angular diameter of the Moon is less than the angular diameter of the Sun.
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Annular eclipse
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The shadow area behind the Earth or Moon where the Sun is completely obscured.
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Umbra
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The shadow area behind the Earth or Moon where the Sun is partially obscured.
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penumbra
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Centered on the earth
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geocentric
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