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65 Cards in this Set
- Front
- Back
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1 AU
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93 million miles
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Earth to sun
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1 au
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three types of planets
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gas giant (Jovian), terrestrial, ice body
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biggest of terrestrial
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earth
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who discovered uranus
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william herschell
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who discovered asteroids ceres?
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Giuseppe Piazzi
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who discovered neptune?
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john couch adams
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who discovered pluto
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clyde tombaugh
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defintion of planet
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celestial body in orbit around sun and round shape, has to have cleared the neighborhood around its orbit
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dwarf planet
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in orbit around sun, round shape, has not cleared neighborhood
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Kepler
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Nasa launched. Stares at piece of the sky to see if a planet crosses in front of a star. Called transiting. Point is to find earth-sized planets
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contellation
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groupings of stars that have a historical reference to a mythological figure, animal, object. There are 88 constellations
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asterism
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small part of constellation that has interesting shape
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how long ago are we viewing the sun?
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8 min 20 sec
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1 degree
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60 arcminutes
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1 arcminute
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60 arcseconds
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1 degree
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3600 arcseconds
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as seen from 5 km (3 miles), 1 arcsecond would be
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size of a quarter
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horizon. what altitude
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where the dome meets the Earth. 0 degree altitude
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zenith. what altitude
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point directly overhead. 90 degree altitude
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altitude
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height of a star above horizon
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azimuth
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direction to star measured true north
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true north has azimuth of
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0
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east has azimuth of
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90
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south has azimuth of
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180
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west has azimuth of
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270
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correction for charlottesville true north is
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9.5 degrees
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latitude
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north-south position on Earth.
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Equator has latitude of
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0 degrees
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North has latitude of
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90 degrees N
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South has latitude of
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90 degrees S
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Longitude
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east-west position on Earth
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Prime meridian
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Greenich, England. Longitude 0 degrees
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Earth turns in what direction? How do the stars look?
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Earth turns west to east so it appears the stars move east to west.
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When standing still, how fast are we moving?
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800 mph to east
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stars appear to go XX around the Nortth Celestial Pole
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counter clockwise
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On what point on Earth do we move fastest?
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Equator
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spring equinox
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0 degrees right ascension
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declination
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north-south position of a star. Measured in degrees, arcmin, arcsec
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celestial equator has a declination of
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0 degrees
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right ascension
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east-west position of a star
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how do you measure right ascension?
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wait until the vernal equinox crosses the meridian
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the path of the sun through the sky is
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ecliptic
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the sun travels through
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12 constellations (13 actually)
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altitude of NCP is equal to
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observer's latitude
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altitude of SCP is equal to
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negative observer's latitude
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the max altitude of celestial equator is
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90 -(observer's latitude)
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the declination of the zenith is equal to
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observer's latitude
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declination of the north horizon is equal to
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90- observer's latitude
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declination of south horizon
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90 + observer's latitude
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Vernal (spring) equinox
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March 21. Location where the sun crosses the equator when going from south of the equator to north of the equator. Position of the sun RA 0 h, Dec. 0 degrees
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Summer solstice
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June 21. location where the sun is furthest north. Position of the sun RA 6 h Dec. +23.5 degrees
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Autumnal (Fall) Equinox
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Sept 21. Where the sun crosses the equator when going from north to south. Position of the sun RA 12 h Dec. 0 degrees
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Winter solstice
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Dec. 21. Location where Sun is furthest south. Position of the sun RA 18 h Dec. -23.5 degrees
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Tropic of Cancer
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Sun will appear directly overhead to someone at 23.5 degrees N latitude. That latitude is this
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The Sun does not set for whom?
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within 23.5 degrees of North pole. (above Arctic circle)
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The Sun does not rise for whom?
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witihn 23.5 degrees of South pole (below antarctic circle)
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Earth is closest to the sun when? when is it farthest?
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January; July
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The axis by which the Earth rotates is tilted by XX degrees with respect to the ecliptic.
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23.5
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At the north pole, the sun will rise and set when?
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rise March 21 and set Sept 21
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For someone standing on the equator, the sun is directly overhead (at the zenith) how often?
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twice per year.
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The most important factor in creating our seasons is
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the angle that sunlight strikes the ground
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What is the maximum altitude of the Sun on June 21 as seen from Charlottesville (38 degrees)?
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75.5
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What is the maximum altitude of the Sun on Dec. 21 as seen from Charlottesville (38 degrees)?
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28.5
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asterism
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small part of a constellation that has an interesting shape
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