Rulerships, Exaltations, Detriments & Fall of Planets

Rulership:  The natural Planetary Sponsor-Director of a sign's energy focus.  This position allows the planet's potential to be delivered in its proper manner through the sign & psyche.

Detriment:  the sign opposite to the one it rules. The sign is  uncomfortable; a frustrated environment for the planet to express itself. 

Exaltation:  the sign that creates the most powerful complement for the planet’s energies.

Fall:  A sign opposite its exaltation. This is the weakest, least effective position for the planet to be in.
 

(One memory trick I use to remember this is that “The Exalted May Fall” if they abuse power.  I also think of “Research and Development {R & D}” for Rules and Detriments.)

NOTE: If a planet in the sign of its fall or detriment is placed in its natural house, or a house which corresponds to its sign of exaltation, then some of the weakness would be neutralized. The same principle applies also to planets found in their dignity and exaltation. The Sun exalted in Aries would be more challenged in the seventh house (natural house of Libra) or the eleventh house (natural house of Aquarius).

A planet is strengthened (dignified) if it falls within the sign that it rules. For example, the Moon in Cancer is considered "strong" (well-dignified). Seventeenth-century astrologer William Lilly compared rulership to a king on his throne, with considerable dignity. If a planet is in the sign opposite that which it rules, it is said to be weakened (detriment), for example, the moon in Capricorn.

In addition to Essential Dignity, the traditional astrologer considers the Accidental Dignity of planets. This is placement by the house in the chart under examination. Accidental dignity describes the planet's "ability to act". So we might have, for example, Moon in Cancer, dignified by rulership, is placed in the 12th house it would have little scope to express its good nature. The 12th is a cadent house as are the 3rd, 6th,  and 9th, and planets in these houses are considered weak or afflicted. On the other hand, Moon in the 1st, 4th, 7th, or 10th would be more able to act as these are Angular houses.

Planets in Succedent houses of the chart (2nd, 5th, 8th, 11th) are generally considered to be of medium ability to act. As well as Accidental Dignity, there is a range of Accidental Debilities, such as retrogradation, Under the Sun's Beams, Combust, and so forth.

Signs shown in parentheses show ancient rulerships. Pluto has not yet been firmly established as it is the most recent planet discovery. Sakoian and Acker’s The Astrologer’s Handbook lists Pluto in exaltation in Leo; this would put its fall in Aquarius.  Most likely, it rules Scorpio and gives dignity to Aries; its detriment is likely in Taurus.  Mars was the ancient ruler of Scorpio and therefore is somewhat dignified in Scorpio, and so on.

Some planets have dual rulership (as indicated).

Planet	Rulership	Detriment	Exaltation	Fall
Sun	Leo	Aquarius	Aries	Libra
Moon	Cancer	Capricorn	Taurus	Scorpio
Mercury	Gemini (Virgo)	Sagittarius (Pisces)	Aquarius	Leo
Venus	Taurus (Libra)	Scorpio (Aries)	Pisces	Virgo
Mars	Aries (Scorpio)	Libra (Taurus)	Capricorn	Cancer
Jupiter	Sagittarius (Pisces)	Gemini (Virgo)	Cancer	Capricorn
Saturn	Capricorn (Aquarius)	Cancer (Leo)	Libra	Aries
Uranus	Aquarius	Leo	Scorpio	Taurus
Neptune	Pisces	Virgo	Libra	Aquarius