phase angle زاویهی ِ فاز zâviye-ye fâz (#) Fr.: angle de phase Physics: Of a → periodic wave,
the number of suitable units of angular
measure between a point on the wave and a reference point.
Astro.: For an object in the solar system, the angle “Sun-object-Earth”
that is, the angle between the Sun and the observer as seen from the given object.
It is 0° when the object is fully illuminated, 90° when the object is
half-illuminated (like the Moon at first quarter and last quarter),
and 180° when the object is between Earth and the Sun.
More generally, the angle between star light incident onto a related revolving
object and the light reflected from the object to the observer (Earth).
See also: → phase; → angle. |
