Phase angle (astronomy)
= Phase angle
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= Phase angle
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The astronomical <phase angle> is the <angle> at an illuminated body between the directions to its light source and to its observer. For a <lunar phase> it is the <Sun>–<Moon>–observer <angle> at the <Moon>, rather than the <elongation> measured at <Earth>. A small <phase angle> gives a nearly full apparent disk in the spherical model.