Quadrature (astronomy)
Encyclopedia
In astronomy
, quadrature is that aspect of a heavenly body
in which it makes a right angle
with the direction of the Sun
. It is applied especially to the apparent position of a superior planet, or of the Moon
at first and last quarters.
As shown in the following diagram, a planet (or other object) can be at the western quadrature (when it is to the west of the Sun when viewed from the Earth) or at the eastern quadrature (when it is to the east of the Sun when viewed from the Earth). Note that an inferior planet can never be at quadrature to the reference planet.
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
, quadrature is that aspect of a heavenly body
Heavenly Body
is a yaoi manga anthology by Takashi Kanzaki and published by Daitosha. It is licensed in English by Aurora Publishing, which released the manga in August 2008.-Reception:...
in which it makes a right angle
Right angle
In geometry and trigonometry, a right angle is an angle that bisects the angle formed by two halves of a straight line. More precisely, if a ray is placed so that its endpoint is on a line and the adjacent angles are equal, then they are right angles...
with the direction of the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
. It is applied especially to the apparent position of a superior planet, or of the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
at first and last quarters.
As shown in the following diagram, a planet (or other object) can be at the western quadrature (when it is to the west of the Sun when viewed from the Earth) or at the eastern quadrature (when it is to the east of the Sun when viewed from the Earth). Note that an inferior planet can never be at quadrature to the reference planet.