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phase angle
phase angle The angle between the Sun and an observer as seen from the centre of a body in the Solar System. At a phase angle of 0° the Sun and observer lie in exactly the same direction, and so the observer sees the object fully illuminated. At a phase angle of 180° the Sun and observer lie on opposite sides of the body, and the whole of its unilluminated side is facing the observer.
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"phase angle." A Dictionary of Astronomy. 1997. Encyclopedia.com. 1 Jun. 2012 <http://www.encyclopedia.com>. "phase angle." A Dictionary of Astronomy. 1997. Encyclopedia.com. (June 1, 2012). http://www.encyclopedia.com/doc/1O80-phaseangle.html "phase angle." A Dictionary of Astronomy. 1997. Retrieved June 01, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O80-phaseangle.html |
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phase angle
phase angle The angle, usually termed α, formed by lines joining the centres of the Earth, the Sun, and another solar system object. Aristarchus of Samos (third century BC) measured the Earth–Sun–Moon angle for the first lunar quarter and thus established that the Sun was much more distant than the Moon.
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AILSA ALLABY and MICHAEL ALLABY. "phase angle." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 1 Jun. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "phase angle." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (June 1, 2012). http://www.encyclopedia.com/doc/1O13-phaseangle.html AILSA ALLABY and MICHAEL ALLABY. "phase angle." A Dictionary of Earth Sciences. 1999. Retrieved June 01, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-phaseangle.html |
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