In astrology, this is the widest possible aspect comprised of two or more planets at 180 degrees. The opposing factor stimulates awareness, and suggests the use of a strategy and diplomacy. The opposition expresses a ying-yang match up of opposing or complementary energies.

Opposition is the astronomical state of a planet (or other body) being directly opposite the sun as seen from the earth. Only the superior planets (Mars, Jupiter, Saturn, Uranus and Neptune) can reach opposition. In addition, the moon, as a satellite, goes into opposition, but at such times it is usually referred to by the more colloquial "full moon".

From the viewpoint of the Earth, a planet reaches opposition about once a year, plus the time that it takes the earth to catch up with the planet's motion. This is something that is hard to explain in words, but is rather simple in a diagram. For instance, Saturn moves very slowly across the sky, so by the time the Earth has returned to its former position in orbit, it has almost caught up with Saturn, and opposition occurs in about the same place. On the other hand, with Mars, by the time that the Earth has caught up with the position where Mars had been in opposition the previous year, Mars has already moved on, and thus the time between Mars' oppositions is greater than that between Saturn's oppositions.

Opposition is also, ceterus paribus, the time when a planet is at its brightest. There are other factors with this, such as whether the planet is at or close to aphelion, or (in the case of Saturn), whether it is presenting its rings towards the Earth. A planet at opposition, being 180 degrees away from the sun, will also rise at sunset and thus will be free for viewing throughout the night.

Op`po*si"tion (?), n. [F., fr. L. oppositio. See Opposite.]


The act of opposing; an attempt to check, restrain, or defeat; resistance.

The counterpoise of so great an opposition. Shak.

Virtue which breaks through all opposition. Milton.


The state of being placed over against; situation so as to front something else.



Repugnance; contrariety of sentiment, interest, or purpose; antipathy.



That which opposes; an obstacle; specifically, the aggregate of persons or things opposing; hence, in politics and parliamentary practice, the party opposed to the party in power.

5. Astron.

The situation of a heavenly body with respect to another when in the part of the heavens directly opposite to it; especially, the position of a planet or satellite when its longitude differs from that of the sun 180°; -- signified by the symbol ; as, .

6. Logic

The relation between two propositions when, having the same subject and predicate, they differ in quantity, or in quality, or in both; or between two propositions which have the same matter but a different form.


© Webster 1913.

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