Zodiac Decans
Each zodiac sign has three 10-degree bands. Find your Sun's band first, then explore the interpretations and ruler conventions used in this collection.
How to Identify Your Decan
Use your Sun's tropical sign and degree to identify its decan. Calendar dates are approximate; your birthday alone may not settle a boundary placement. If your birth time is unknown, a representative position near a boundary may leave your decan uncertain.
This collection uses modern triplicity: sub-rulers follow the signs of the same element. Other systems, including Chaldean decans, assign different rulers. The descriptions below are interpretive traditions, not measured personality traits. Compare the decan methods at Astrodienst.
From 232.5° to a Decan
These are invented chart coordinates for learning, not a real birth or astronomical event. Suppose a tropical chart gives the Sun's full-circle longitude as 232.5°. Scorpio starts at 210°, so subtract the start of the sign:
232.5° − 210° = 22.5° within Scorpio = 22°30′ Scorpio.
The band from 20° up to but not including 30° is the third decan of Scorpio. For this same band, modern triplicity assigns the Moon; the Chaldean system assigns Venus. These are different interpretive conventions, not different positions of the Sun. See Astrodienst's ruler tables.
| Illustrative full-circle longitude | Degree within Scorpio | Decan |
|---|---|---|
| 229°59′59″ | 19°59′59″ | Second |
| 230°00′00″ | 20°00′00″ | Third |
Rounding both values to a whole degree would hide the difference. Choose the band first. When reading your own chart, check that the selected body is the Sun, the zodiac is tropical, and you are using the degree within the sign. Keep any unknown birth-time uncertainty visible.
Find Your Sun's Decan
Calculate your birth chart to see your Sun’s sign, degree and decan above your general chart. Within that sign, 0° up to but not including 10° is the first decan; 10° up to but not including 20° is the second; 20° up to but not including 30° is the third.
If your birth time is unknown, the displayed degree is representative. Near a sign or decan boundary, it may not establish your decan; a confirmed birth time may be needed.
Find My Sun's Decan