What is Opposition in Western astrology?

Definition

Opposition is a Western astrological aspect in which two planets sit 180 degrees apart in the zodiac, enclosing two right angles and six signs, as Ptolemy's Tetrabiblos describes it.

In plain words

Opposition is a Western astrological aspect, meaning two planets sit 180 degrees apart in the zodiac, or on opposite sides of a straight line through the chart. Ptolemy's Tetrabiblos, published in the Loeb Classical Library in 1940, lists it among the aspects and describes it as enclosing two right angles, six signs, and 180 degrees. Astronomers use the same 180-degree idea for a separate event, the instant when a body's apparent geocentric longitude differs by 180 degrees from the Sun's.

Also asked as

• What angle is an opposition?
• What orb is usually used for an opposition?
• Is an opposition harmonious or challenging?
• How is an opposition shown on a chart?

History

Ptolemy's Tetrabiblos, published in the Loeb Classical Library in 1940, lists opposition among the aspects. He describes it as enclosing two right angles, six signs, and 180 degrees, a measure that the Loeb edition carries into English for modern readers.¹

Manilius, a classical astrologer, explained that opposing signs are divided by a line, and he tied the aspect to the symbolism of the number two. Deborah Houlding, writing for Skyscript, reports that this divisive symbolism makes the opposition the epitome of separation and enmity in the classical sense.⁵

Skyscript's glossary links the opposition to the divisive Pythagorean principles of the line, which are associated with the number two.⁶⁴

Quick timeline

1. Early record — Ptolemy's Tetrabiblos, published in the Loeb Classical Library in 1940, lists opposition among the aspects. He describes it as enclosing two right angles, six signs, and 180 degrees, a measure that the Loeb edition carries into English for modern readers.¹
2. Classical framework — Manilius, a classical astrologer, explained that opposing signs are divided by a line, and he tied the aspect to the symbolism of the number two. Deborah Houlding, writing for Skyscript, reports that this divisive symbolism makes the opposition the epitome of separation and enmity in the classical sense.⁵
3. Later transmission — Skyscript's glossary links the opposition to the divisive Pythagorean principles of the line, which are associated with the number two.⁶⁴
4. Modern usage — Ptolemy explains that opposition is immediately obvious because it causes the signs to meet on one straight line, and he derives it by applying the fraction one-half to the two-right-angle interval. Ptolemy classes opposition with the quartile as disharmonious, because the signs it joins are of opposite kinds, masculine and feminine, unlike the harmonious trine and sextile. According to the Skyscript article by Deborah Houlding, the classical opposition was not a friendly aspect; only occasionally was it taken to represent agreement, usually between conflicting parties who struck up an unstable alliance.¹⁵⁶

What classical and modern sources say

Classical view

Ptolemy explains that opposition is immediately obvious because it causes the signs to meet on one straight line, and he derives it by applying the fraction one-half to the two-right-angle interval. Ptolemy classes opposition with the quartile as disharmonious, because the signs it joins are of opposite kinds, masculine and feminine, unlike the harmonious trine and sextile. According to the Skyscript article by Deborah Houlding, the classical opposition was not a friendly aspect; only occasionally was it taken to represent agreement, usually between conflicting parties who struck up an unstable alliance.¹⁵⁶

Modern view

Modern approaches often frame the opposition as a hard aspect. Wikipedia's aspect overview says hard aspects may be negative because they enhance a challenge where an adjustment must be made to reach balance, which is how an opposition is framed in the modern approach. The opposition is one of the traditional Ptolemaic major aspects, defined at 180 degrees, and it appears among the aspects of the Kepler-era harmonic series. Skyscript describes it as a very strong and forceful aspect, because the planets have a clear and direct full-on view of each other, and notes that it can be harsh or destructive when one or both planets are malefics or defined as unfortunate.⁴⁶

Angle, orb and interpretation

Exact angle

Opposition is the 180-degree relationship between two zodiacal longitudes, which Ptolemy's Tetrabiblos describes as enclosing two right angles and six signs. Skyscript's glossary entry, authored by Deborah Houlding, identifies the opposition with the symbol X and sets it as a 180-degree separation between planets in the zodiac.¹⁶

Orb

A common allowance is 6 to 8 degrees. Orb conventions vary and are not astronomical constants, so a reader should check which allowance a given school or author uses.¹

Interpretive frame

Usually described as challenging, an opposition presents two ends of an axis to balance and integrate rather than an unavoidable conflict. Ptolemy notes it is a diametral aspect, which he judges inconsistent with beneficence when Saturn's signs are set opposite Cancer and Leo.¹

Geometry

Two rays separated by 180 degrees show the geometric definition without treating interpretation as a measured force. Each planet is seen from the other across the full width of the chart circle.¹⁶

The astronomy

The instant of opposition is defined as when the apparent geocentric celestial longitude of a body differs by 180 degrees from the apparent geocentric longitude of the Sun. Opposition occurs only for superior planets. Seen from a superior planet, an inferior planet on the opposite side of the Sun is in superior conjunction with the Sun, while an inferior conjunction places the superior planet in opposition as seen from the inferior planet.³

Usually described as challenging, an opposition presents two ends of an axis to balance and integrate rather than an unavoidable conflict.¹

Where astrologers differ

Ptolemy classes opposition with the quartile as disharmonious, because the signs it joins are of opposite kinds, masculine and feminine, unlike the harmonious trine and sextile. Houlding, writing for Skyscript, notes that although the opposition is unfriendly, it is a very strong and forceful aspect because the planets have a clear and direct view of each other. The astronomical sense differs from the astrological one: opposition in astronomy describes a body's position relative to the Sun for superior planets only.

Then and now

Then

Ptolemy explains that opposition is immediately obvious because it causes the signs to meet on one straight line, and he derives it by applying the fraction one-half to the two-right-angle interval. Ptolemy classes opposition with the quartile as disharmonious, because the signs it joins are of opposite kinds, masculine and feminine, unlike the harmonious trine and sextile. According to the Skyscript article by Deborah Houlding, the classical opposition was not a friendly aspect; only occasionally was it taken to represent agreement, usually between conflicting parties who struck up an unstable alliance.¹⁵⁶

Now

Modern approaches often frame the opposition as a hard aspect. Wikipedia's aspect overview says hard aspects may be negative because they enhance a challenge where an adjustment must be made to reach balance, which is how an opposition is framed in the modern approach. The opposition is one of the traditional Ptolemaic major aspects, defined at 180 degrees, and it appears among the aspects of the Kepler-era harmonic series. Skyscript describes it as a very strong and forceful aspect, because the planets have a clear and direct full-on view of each other, and notes that it can be harsh or destructive when one or both planets are malefics or defined as unfortunate.⁴⁶

Worked out from the evidence

Reasoned from the cited facts, not stated outright by any one source.

Because Ptolemy classes opposition as disharmonious and Skyscript's Deborah Houlding calls it a strong, forceful aspect, a reader can take the opposition as intense and sharply contrasting rather than as an easy, friendly link between planets.

Ptolemy's 1940 Loeb Classical Library edition and the Wikipedia opposition article both fix the 180-degree measure, so the angle is stated consistently across a classical text and a modern reference even though their purposes differ.

Not yet confirmed

• How much orb the classical authors allowed for an opposition is not fixed across the sources, so readers must check each author's own allowance.

Follow the parts of Opposition

Continue through Trine, Conjunction.

Questions people also ask

What angle is an opposition?

An opposition is the 180-degree relationship between two zodiacal longitudes, which Ptolemy's Tetrabiblos describes as enclosing two right angles and six signs. Skyscript's glossary entry, authored by Deborah Houlding, sets it as a 180-degree separation between planets in the zodiac.¹⁶

What orb is usually used for an opposition?

A common allowance is 6 to 8 degrees, according to the Tetrabiblos reference. Orb conventions vary and are not astronomical constants, so a reader should check which allowance a given school or author uses.¹

Is an opposition harmonious or challenging?

Ptolemy classes opposition with the quartile as disharmonious, because the signs it joins are of opposite kinds, masculine and feminine. Skyscript's Deborah Houlding adds that it is a very strong and forceful aspect because the planets have a clear and direct view of each other.¹⁵

Method and review

Every statement about Opposition was checked against the wording of its 6 sources (Ptolemy (LacusCurtius), Encyclopaedia Britannica, Wikipedia and Skyscript), and its positions and boundaries were calculated with Astronomy Engine. How the Machine works.