Practicing Astrology directly from observations of the night sky is a bit different from working directly out of an Ephemeris, or using a computer to sketch horoscopes of the current celestial spheres! Decans were a practical innovation, and were originated by Astrologer-Astronomers who were watching the night sky some 4,100 years ago....
The Zodiac itself was developed as a convenience by those ancient Stargazers. It's rhythmic 30 degree durations suited endeavors of describing the experiential sky. While our familiar 12-sign Zodiac follows Solar rhythms (Lunar-based systems require 13 signs to complete a year's cycle), its division into months still acknowledges the Moon's brisk circuit of the Zodiac, an event lasting about 28 days. The Moon's name is even preserved within the nomenclature; woven, as it is, into the word "month".
Sitting at the edge of luminescence, along the limn-line of a first-quarter Moon, surface details are sharply outlined by the shadows falling there. They will wane in the gathering light, flattening their edges, and smoothing-out, much like the large crater on the bright surface above them (center left).
Yearly, monthly & daily solar/lunar interrelationships & their cycles are explored on Starlit Path, via multiple animated illustrations in 'Risings'...
Prior to development of the Zodiac as we know it, fixed stars were used alone, by those early observers. Notable stars, centered near the Ecliptic, rose in a predictable fashion above the local horizon. Any bright stars just-rising on the horizon could be used to mark the hours of the night.
Gradually, these prominent marker stars were named; often they were linked to cultural dieties or characters of mythical proportion. Later, they were connected together, along with some of their immediate neighbors, and grouped into larger figures that spanned whole sections of the sky. They, too, were characters in the ancient myths. These have evolved into our familiar Constellations. Those lying along the narrow band of the Ecliptic became the signs of the Zodiac. It is as it was: the only area of the sky where planets traveled, hence the only place in the sky where an eclipse could possibly arise. (The word "planet" is dervied from a Greek word for "wanderer".)
Because of Earth's progress in its orbit around the Sun, a rising-star will slowly move above the horizon, a little more each night, until it's no longer ascending at the given time. Thus, any specific star, or stars had to be changed about every 10 days. A fact well known among Astronomers is that most constellations are visible only during certain seasons of the year. Earth's progress, through her annual circum-solar trek, moves all but the polar stars above her horizons for a time, and then below them, in due course.
Our Earthbound viewpoint also sees this progress via the apparent motion of the Sun through the Zodiac. It 'moves' forward nearly a degree per day. Hence the decans (or decanates) were born, even before the Zodiac they now help define. They survive today as one-third divisions ( 10° ) of each sign.

Delivered Out of Egypt
The earliest records of decans appeared in Egypt around 2100 BC. Archeologists have found them portrayed as their fully developed characters in metal and stone artifacts. Normally depicted on the ceilings of culturally important buildings (temples and tombs) they were given names, and distinctive characteristics. Often, they were portrayed as sailing in small boats.
Discovered in their native land by visiting Greeks, they were imported wholesale into the growing bounty of Astrological knowledge collecting there. Egyptians were among the earliest known peoples to look for personal meaning from the stars. Most Astrologers in those days were prognosticators, employees of governments and kingdoms, generally concerned with the welfare of the state; their art rarely focused on issues of personal growth!
Hermes, an early Astrological writer (some two millenia after the decans first appeared in Egyptian architecture), regarded both the Zodiac and the Universe as circular. He described planets and the Universe as physical bodies. The 36 decans were viewed as if placed below the circle of this body (the Universe). The decans were thought to sit between the circle of the Zodiac and the circle of the Universe, bearing up the one, and looking down upon the other.
So, they were pillars of the night, and of the dawn, vaulting the very arc of the heavens, holding it high above the Earth. They were thought to have special powers, being exempt from things that befall the other stars. They were seen as careful guardians and overseers of the Universe, traveling around it in the space of a night and a day; they accompanied souls across the chasm between this world and the next. They were powerful forces for good or ill, depending upon the general climate of all things heavenly, and the mood of these six and thirty gods. They could exert their powers upon the Earth and other planets, which in turn had effects upon humankind.
Hawk-headed Horus was a chief Egyptian diety. However, other figures frequently appeared in heiroglyphs with the head of a hawk, including numerous Decans recorded on the round ceiling of the Temple of Hathor at Denderah.
This stylized figure holds the ankh, an Egyptian symbol of eternal life. It's a subject which apparently held a great deal of interest for that early-day culture.
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Astrological Rulership and the Decanates
![The 36 Decans are shown on a special horoscope wheel, by using a rainbow color-coding of the 12 Zodiac Signs. The innermost ring is similarly colored, and contains the 144 duads [dwads], discussed in the next section of Starlit Path's articles.](Decans%20%27n%20Duads%20-%20Core%20Meanings%20in%20Astrology%20-%20JOANNA%20MILLER%20-%20Astrologer_files/ast_dcan.gif)
Another View of the Decans
Here, they are rainbow color-coded according to their sign of the Zodiac. The 12 signs, with 3 decans each, form the outer rings. As illustrated, any sign's first decan is always the sign itself.
The inner ring contains the 144 duads (dwads), 12 per sign, 4 per decan. Note that the 1st duad in each decan is also the same sign as the decan.
Signs, decans, and duads run counter-clockwise, as numbered.
As stated elsewhere on Starlit Path, 'rulership' is the ultimate key to understanding Astrology. Within whatever section of the horoscope is being referenced, its ruler is the one in ultimate charge of all the things inside that sphere. The ruler is also described as having 'lordship', or even 'dominion' over its area.
As in many other cases in Astrology, complete agreement among Astrologers has not been reached regarding the decans. At least two early techniques of assigning rulerships can be discovered in surviving Astrological manuscripts.
A Secondary Style
An alternate method of assigning decanate rulership reflects very similar motifs seen in other classical techniques. Like them, it engages a system of purely planetary dominion in a prescribed sequential order.
Starlit Path addresses it only briefly, and only here...
Beginning (and ending) with Mars, the 36 decans (starting with 0° Aries) are ruled consecutively, by a rigidly-sequenced arrangement of the 7 visible planets. They are:

Mars, Sun, Venus, Mercury, Moon, Saturn, Jupiter.
The series establishes itself, in that order, through decans 1 through 7, begins anew at 8 and runs in the same order through 14. It then repeats itself in decans 15-21, 22-28, 29-35 respectively. It stops with Mars, as ruler of number 36 (from 20°-30° [actually to 29°59'59"] Pisces).
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Primary Method of Decan Rulership

This rulership scheme employs the 12 signs and their associated planets for ruling individual decans (and carries right on over into duads' rulerships, as well). The basis for determining rulership hinges on two prominent Zodiac characteristics: the triplicities (also called elements), and the quadriplicities (also called modes, types, or qualities).
- Signs are first grouped together by their element, whether Fire, Earth, Air, or Water. Each element's group includes all the modes/qualities of that element, whether Cardinal, Fixed, or Mutable.
- Any given sign's triad of divisions-as-decans are ruled by that sign's three same-element signs.
- The first decan of a sign is ruled by that sign. For example, the first decan of Aries is ruled by Aries; the first decan of Taurus is ruled by Taurus; the first decan of Gemini is ruled by Gemini, etc.
- The second decan's ruler is the next-encountered same-element sign, following in normal Zodiacal order. The next fire-sign following Aries is Leo, so it rules Aries' second decan. The earth-sign following Taurus is Virgo, so it rules Taurus' second decan.
- The final same-element sign, proceeding in normal order from there, rules the third decan. Sagittarius is the fire-sign trailing after Leo, so it rules the third decan of Aries. Capricorn rules Taurus' third decan.
Discussion of decan rulership continues here....
Links, above, lead to a colorful expansion of information about elements, qualities, and their associated aspects.
Amplified section includes links to interpretations* of the 36 decans. They are also accessible from the table below. Click on the Zodiac sign to see the decans of that sign. Each one links to interpretive keywords & phrases.
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*These are broad & general. See explanation that follows table below...
The Associations
Each sign glyph in the chart above holds a link to that sign in another, similar chart. The second chart shows the decans for each sign and has direct links to meanings* for each decan.
*Please note that these readings are only generalizations. Other considerations will apply to any individual chart. For futher discussion of such modifying conditions, see sections below...
Planets as Decan Rulers
Planetary co-rulerships are derived from the ruling signs. Both element and quality convey powerful structural and symbolic meaning to every sign, and thus to every decan's 10° division.
the Signs & their Planets Are Rulers
...the Decanates are sub-Rulers...
Thus, for that first decan (0-10°) of Aries, the co-rulerships include the initial, underlying sign of Aries coloring the impulses of whatever planet or point resides there. (Of course, the overall Aries rulership is for the entire sign, and will always be the stronger of the two.) That first Decan, however, is also ruled by Aries. Thus, the rulership is doubled-up: Aries for the sign and Aries for the decanate. This area of the sign is the most powerfully Aries, this is where it's the most like unto itself.
Mars is the planetary ruler of Aries. So, to learn more about this Aries / Aries area of the chart, the Astrologer will take note of any conditions surrounding Mars; including its sign & house placements, as well as its aspects. Mars is really emphasized, if it falls within Aries, but especially if it's within these degrees, because of the double rulership. But almost any planet or important point located in this decan will be more firey and impulsive than anywhere else in the chart. The actual expression may make its appearance as a high level of spontaneity, or a quick-wittedness with intense interest in anything new. ...this is the Aries-Aries!
For the second decan (10-20°) of Aries, the sign Leo will add color to the impulses of any planets there. The Decan (a sub-ruler) is Leo. Its natural ruler is the Sun. Therefore, the Sun's conditions (especially by sign, house, & aspects), give additional information about the degree being examined. In these degrees, one would look to Mars primarily, and the Sun secondarily for further information about the energies at play in this area of the horoscope.
Leonine tendencies will permeate the Aries point or planet falling within these degrees. Adding Leo's fixed nature to the quick, impetuous Aries is likely to result in an energetic person who is more stable, with less initiative-just-for-its-own-sake. The Leonine-Aries is much more likely to endeavor to hold on to what he has. Change will be more difficult for this Aries (though perhaps not by much, as change is a hallmark of Aries!). Leo is very concerned with creativity, and with establishing individuality, and will strengthen Aries tendencies in these areas. The Leonine-Aries will have a significantly different approach to life from his Arian-Aries sibling.
Finally, for the third decan (20-30°) of Aries, we have the sign Sagittarius coloring the impulses of any planet or important point placed there. The Decan (sub-ruler) is Sagittarius. Its ruler is Jupiter, and any special conditions of Jupiter, by sign, aspect or house, will give additional information about the degree in question.
Sagittarius brings his mutable nature to Aries in this decan, and is much more flexible and adaptable than either of his brethren. Not that he doesn't want to shine brightly; Sagittarius is, after all, a fire sign, filled with the inspirations of the Greater Spirit. It's just that he's about as likely to head out on his own, as he is to work hard at dragging a lot of others along with him. Sag is deeply concerned with the quest for truth, with fairness, with justice, and has a strong philosophy of providing a higher, broader education for all. The style and approach to life of the Sagittarian-Aries will certainly be much different from that of either of his two close kin!
Enhancing Our Understanding
![The 36 Decans are shown on a special horoscope wheel, using color-coding to differentiate the elements and modes of the 12 Zodiac Signs. The innermost ring is similarly color-coded, this time by element, and contains the 144 duads [dwads].](Decans%20%27n%20Duads%20-%20Core%20Meanings%20in%20Astrology%20-%20JOANNA%20MILLER%20-%20Astrologer_files/decans-d.gif)
Illustrating the Decans
· Fire
· Earth
· Air
· Water
· Cardinal
· Fixed
· Mutable
The presence and positioning of the various Decans is amplified in the graphic above, by placing them adjacent to the 12 signs of the Zodiac. Each sign's glyph has a unique combination of two longer-color-bars immediately surrounding it. These represent its Element [outside] & Quality/Mode [inside].
The 3 decans of each sign, are arrayed by their Quality: cardinal, fixed, or mutable.
Arrows mark the Angles of the chart, where cardinal signs are lodged. These correspond to the changing of the seasons of the year, and are numbered 1, 4, 7, & 10 in the graphic.
The natural order of the 12 Zodiac signs is counter-clockwise, as numbered.
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Just as the decanates were developed as a result of the progress of the Earth during its annual trek around the Sun, it's the signs' progressive qualities that we're modifying by observing the decanates. Rulerships for the 10° decan-subdivisions are assigned according to the harmonics of their own element, because fire goes best with fire, earth with earth, etc.
So, Zodiac signs, from the three qualities of each sign-element, are used to rule the three decans of each whole-sign in that element. Each decan, as sub-ruler of a portion of a sign, brings its own individual characteristics and predispositions to that area of the horoscope. While coloring the decan with unique attributes of its own nature, much like the clarifying effects of brightly tinting the diagrams on this page, it reveals a transformed view capable of attaining greater heights. Suddenly, the sum of the whole becomes more than its parts. Its potentials soar into realms unknown by its structural components; it sees vistas only guessed-at by its brethren.
Perched along the outer rim of the horoscope, the signs of each element rest at 120° angles from one another in the Zodiac circle. Among the aspects, this is an angle of easy flow. Sitting at this angle constitutes an harmonious placement. (Signs of like-quality do not share angles/aspects of easy flow. They share difficult aspects of challenge, reflection and adjustment.)
Since there is innate harmony among the elements, this system of decanate rulerships results in an expansion of meaning via familiar symbolism, that of the Zodiac's signs, with their assortment of ruling planets. It offers a simple but effective means for deeper understanding of each sign, as planets make their way through them, whether by an initial lodging at birth, or by later transit or secondary progression.

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