The decans divide the zodiac into thirty-six ten-degree segments, three to each sign. They originate in Egyptian astronomy as a set of stars used to mark the hours of the night, and were absorbed into Hellenistic astrology, where each decan received a planetary ruler. Two ruler schemes are in common use, the Chaldean order and the triplicity or face system, and the decans also carry the talismanic images described in Arabic and Renaissance magical texts such as the Picatrix.
Facts
Overview
- Entries in the Atlas
- 36
- Size of the Traditional Set
- 36 decans 1
Origins
- Origin Period
- Attested in Egypt from about 2100 BCE, on the diagonal star tables painted inside Middle Kingdom coffin lids 1
- Place of Origin
- Egypt: thirty-six star groups used to mark the hours of the night and the ten-day weeks of the year 1
- Place of Origin
- Then Greco-Roman Egypt, where they were given planetary rulers and images, and onward through Arabic and Latin astrological magic as the "faces" 2
- Origin of the Name
- From Greek dekanos, "of ten", for the ten-degree span; the Egyptian originals were the star groups that marked the ten-day weeks. 1
Structure
- Structure
- Thirty-six ten-degree segments, three to each sign, ruled either in the Chaldean planetary sequence or by the triplicity of the sign's element. 2
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The thirty-six divisions of the zodiac
The decans divide the zodiac into thirty-six ten-degree segments, three to each sign. They originate in Egyptian astronomy as a series of stars used to mark the hours of the night and the passage of the year, and were absorbed into Hellenistic astrology, where each decan received a planetary ruler and a set of images.
Two main schemes of rulership exist: the Chaldean order, which runs the seven planets in sequence through the decans, and the triplicity scheme, which assigns the decans of each element by that element's signs. Each decan also acquired pictorial images, the most famous being those of the Picatrix and the "faces" of medieval astrology.
A finer grain of meaning
The decans give the astrologer a finer division than the sign, letting a planet in, say, the first ten degrees of Leo be read differently from one in the last ten. They were important in medieval astrological magic, where the decan images were carved as talismans, and they connect to the Egyptian star-calendar from which they sprang.
The atlas gives each decan its degrees, its rulers under the main schemes, and its traditional images. The decans sit among the finer tools of the chart alongside the fixed stars, the Sabian symbols and the Arabic parts.
Enter a year to compare these entries as the atlas records them at that moment. Leave it empty for the present. A year before the common era is entered with a minus sign, so 44 BCE is minus 44.
Aries
3
Taurus
3
Gemini
3
Cancer
3
Leo
3
Virgo
3
Libra
3
Scorpio
3
Sagittarius
3
Capricorn
3
Aquarius
3
Pisces
3