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21 Cards in this Set

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Celestial sphere
The hypothetical sphere centered at the center of the Earth to which it appears that the stars are affixed.
Dictionary: An imaginary sphere of infinite extent with the earth at its center on which the stars, planets, and other heavenly bodies appear to be located.
Angular distance on the earth's surface, measured east or west from the prime meridian at Greenwich, England, to the meridian passing through a position, expressed in degrees (or hours), minutes, and seconds.
The angular distance around a body measured along the equator from some particular point; for a point not on the equator, it is the angular distance along the equaotr to a great circle that passes through the poles and through the point.
Number of degrees north or south of the equator measured from the center of a coordinate system.
North Pole
True North. Latitude 90 degrees north.
The northern end of the earth's axis of rotation, a point in the Arctic Ocean.
The celestial zenith of this terrestrial point.
north pole The northern end of the axis of rotation of a planet or other celestial body
Soth Pole
The Geographic South Pole is the point where the earth's axis of rotation intersects the surface.
a point in Antarctica.
The celestial zenith of this terrestrial point.
south pole The southern end of the axis of rotation of a planet or other celestial body.
a) Of the Earth, a great circle on the Earth, midway between the poles;
b) celestial, the projection of the Earth's equator onto the celestial spheres;
celestial poles
The intersection of the celestial sphere with the axis of rotation of the Earth
celestial equator
The intersection of the celestial sphere with the plane that passes through the Earth's equator.
Prime Meridian
The zero meridian (0°), used as a reference line from which longitude east and west is measured. It passes through Greenwich, England.
Right Ascension
Celestial Longitude, measured eastward along the celestial equator in hours of time from the vernal equinox.
Celestial latitude, measured in degrees north or south of the celestial equator.
The apparent intersection of the earth and sky as seen by an observer. Also called apparent horizon.
Of or relating to a reference system based at the center of the sun.
Having the sun as a center.
Relating to, measured from, or with respect to the center of the earth.
Having the earth as a center.
A cluster of stars smaller than a constellation.
a pattern of stars seen in Earth's sky which is not an official constellation, such as The Big Dipper in Ursa Major or The Teapot in Sagittarius.
An arbitrary formation of stars perceived as a figure or design, especially one of 88 recognized groups named after characters from classical mythology and various common animals and objects.
An area of the celestial sphere occupied by one of the 88 recognized constellations.
A star of the second magnitude, at the end of the handle of the Little Dipper and almost at the north celestial pole. Also called North Star, polar star, polestar.
Circumpolar Constellations
those stars which are located near the poles of the celestial sphere. As the Earth rotates, the sky appears to rotate; and most stars will be hidden below the horizon at some point in their circular paths. If, from a certain location, a star is near enough to the celestial pole that it never appears to go "under the horizon"; it will therefore be visible (from said location) for the entire night, on every day of the year.
Zodiac Constellations
The band of constellations through which the Sun, Moon, and planets move in the course of a year.
Big Dipper
A cluster of seven stars in the constellation Ursa Major, four forming the bowl and three the handle of a dipper-shaped configuration. Also called Charles's Wain, Plow.
Little Dipper
The seven bright stars that form the constellation Ursa Minor.