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Planetary phase. The evolution of the apparent diameter and phases of Venus. A planetary phase is a certain portion of a planet 's area that reflects sunlight as viewed from a given vantage point, as well as the period of time during which it occurs. The phase is determined by the phase angle, which is the angle between the planet, the Sun and ...
In this situation, the latter planet is said to be superior to the former. In the reference frame of the Earth, where the terms were originally used, the inferior planets are Mercury and Venus, while the superior planets are Mars, Jupiter, Saturn, Uranus and Neptune. Dwarf planets like Ceres or Pluto and most asteroids are 'superior' in the ...
In astronomy, a planet's elongation is the angular separation between the Sun and the planet, with Earth as the reference point. [1] The greatest elongation is the maximum angular separation. Astronomical tables and websites, such as Heavens-Above, forecast when and where the planets reach their next maximum elongations.
Phase angle (astronomy) Phase angle diagram. In observational astronomy, phase angle is the angle between the light incident onto an observed object and the light reflected from the object. In the context of astronomical observations, this is usually the angle Sun -object-observer. For terrestrial observations, "Sun–object–Earth" is often ...
The phase curve of Venus [15] compared to Mercury, [1] and the brightness excess of Venus.. The relatively flat phase curve of Venus is characteristic of a cloudy planet. [14] In contrast to Mercury where the curve is strongly peaked approaching phase angle zero (full phase) that of Venus is rounded.
In spherical astronomy, quadrature is the configuration of a celestial object in which its elongation is a right angle (90 degrees), i.e., the direction of the object as viewed from Earth is perpendicular to the position of the Sun relative to Earth. It is applied especially to the position of a superior planet or the Moon at its first and last ...
In astronomy, a syzygy (/ ˈ s ɪ z ə dʒ i / SIZ-ə-jee; from Ancient Greek συζυγία (suzugía) 'union, yoking', expressing the sense of σύν (syn-"together") and ζυγ- (zug-"a yoke") [1] [2]) is a roughly straight-line configuration of three or more celestial bodies in a gravitational system.
Deferent and epicycle. The epicycles of the planets in orbit around Earth (Earth at the center). The path-line is the combined motion of the planet's orbit (deferent) around Earth and within the orbit itself (epicycle). In the Hipparchian, Ptolemaic, and Copernican systems of astronomy, the epicycle (from Ancient Greek ἐπίκυκλος ...