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Decan
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What is Decan in Astrology — The Three 10 Degree Divisions of Each Zodiac Sign?
A decan or decanate divides each 30° zodiac sign into three equal 10° sections. Each section carries its own sub-ruler and slightly different flavor within the sign's overall character. Decans add a layer of nuance to any planet's exact degree placement within a sign.
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Decan in Astrology
A decan (or decanate) divides each 30° zodiac sign into three equal 10° sections. Each section carries its own sub-ruler and slightly different flavor within the sign's overall character. Decans add a layer of nuance to any planet's exact degree placement within a sign.
How Decans Work
Each sign has three decans:
- First decan: 0°–9°59' — purest expression of the sign
- Second decan: 10°–19°59' — flavored by the next sign in the same element
- Third decan: 20°–29°59' — flavored by the third sign in the same element
The Modern Decan System (Same-Element Rulers)
In the most widely used modern system, each decan is associated with the signs of the same element in order:
Aries (Fire):
- First decan (0°–9°): Aries sub-tone (Mars)
- Second decan (10°–19°): Leo sub-tone (Sun)
- Third decan (20°–29°): Sagittarius sub-tone (Jupiter)
Taurus (Earth):
- First decan (0°–9°): Taurus sub-tone (Venus)
- Second decan (10°–19°): Virgo sub-tone (Mercury)
- Third decan (20°–29°): Capricorn sub-tone (Saturn)
Traditional Chaldean Decan System
Traditional astrology uses a different assignment — the Chaldean order of planets (Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon) cycling through the decans. This system is used in horary, Hellenistic, and some traditional natal work.
What Decans Mean in Practice
A planet at 2° Scorpio (first decan, purest Scorpio) expresses pure Scorpionic intensity. The same planet at 22° Scorpio (third decan, Cancer sub-tone) carries Scorpionic themes but with an emotionally nurturing, protective overlay — intensity tempered by Cancer's sensitivity.
Decans are most commonly applied to the Sun (giving the three "types" within each sign in decan-based horoscope content) but can be applied to any planet.
Related Terms
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Frequently Asked Questions
First decan (0-9°59' Scorpio): Scorpio sub-tone, ruled by Mars/Pluto. Second decan (10-19°59' Scorpio): Pisces sub-tone, ruled by Neptune/Jupiter. Third decan (20-29°59' Scorpio): Cancer sub-tone, ruled by Moon. Each decan colors the Scorpio energy differently.
Your Sun's decan depends on its exact degree in your sign. If your Sun is at 0-9°59', you're in the first decan; 10-19°59' is the second decan; 20-29°59' is the third decan. Each decan of your Sun sign is further flavored by its sub-ruler.
Some horoscope content divides each sign into three groups and gives slightly different readings for each decan. This is more specific than Sun-sign horoscopes but less precise than a full natal chart reading.
Decans divide each sign into three 10° equal sections with a planetary sub-ruler. Terms (or bounds) divide each sign into five unequal sections, each with a different planetary ruler. Both are traditional subdivision techniques that add nuance beyond the basic sign placement.