Opposition (astronomy and astrology)
Opposition is a word used in astronomy and astrology to show when one celestial body is on the opposite side of the sky when viewed from a particular place (usually the Earth). In particular, two planets are in opposition to each other when their ecliptic longitudes differ by 180°. When the Moon is in opposition it is called full moon.
The symbol of opposition is ☍.
- it is visible almost all night, rising around sunset, culminating around midnight and setting around sunrise;
- its orbit brings it closest to the Earth, making it appear bigger and brighter.
- the opposition effect increases the reflected light from bodies with unobscured rough surfaces
References[change | change source]
- U.S. Naval Observatory Nautical Almanac Office, P. Kenneth Seidelmann (ed) 1992. Explanatory supplement to the Astronomical Almanac. University Science Books, Mill Valley CA, 733. ISBN 0-935702-68-7