Astronomical oppositionOpposition is a term used in positional astronomy and astrology. It means that, as seen from some place (usually the Earth), one celestial body is opposite to another in the sky.
Specifically, two planets are in opposition to each other when their ecliptic longitudes differ by 180°.
- it is visible almost all night (it rises around sunset, culminates around midnight, and sets around sunrise);
- it makes its closest approach to the Earth during its orbit around this time, so it appears biggest and brightest.
See also: conjunction