Knowra Constellation Constellation A constellation is a defined region of the celestial sphere, often associated with a traditional star pattern. Modern constellations divide the entire sky into fixed, officially bounded areas.
Celestial sphere : An imagined sphere surrounding Earth onto which celestial objects appear projected. Constellations mark regions on this apparent sphere, not areas of physical space.
Babylonian astronomy : The systematic study of celestial phenomena by scholars in ancient Mesopotamia. Babylonian star divisions contributed traditions later incorporated into Greek constellation schemes.
Constellation boundary : A formally specified line separating one modern constellation region from another on the celestial sphere. Boundaries make every celestial position belong to a defined constellation, even between its prominent stars.
Zodiac : A belt of the sky along the ecliptic, divided into constellations in astronomy and signs in astrology. Its familiar constellations lie along the Sun’s apparent annual path.
Right ascension : The celestial coordinate analogous to longitude, measured eastward along the celestial equator. Together with declination, it locates positions within constellation boundaries.
Ancient Greek astronomy : The study of the heavens by ancient Greek thinkers, combining observation, mathematical models, and inherited traditions. Greek authors transmitted many familiar constellation names and figures.
Equatorial coordinate system : A celestial coordinate system based on right ascension and declination. Modern constellation borders follow lines of these coordinates.
Celestial navigation : The determination of position or direction using observations of celestial bodies. Recognizable constellations help identify stars used for navigation.
Declination : The celestial coordinate measuring angular distance north or south of the celestial equator. Its lines, paired with right ascension, help define constellation borders.
Ptolemy : A second-century Greek-Egyptian astronomer whose works shaped astronomy for many centuries. His Almagest catalogued 48 constellations that influenced later European star atlases.
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