The Tropical Zodiac

Published Categorized as Fundamentals
The Tropical Zodiac - The ecliptic was divided into 360 degrees with 30 degrees allotted to each of the 12 signs

The development of the zodiac around the fifth century B.C. was an important milestone in the history of astrology. The path of the Sun, the Moon, and the planets around the Earth, also known as the ecliptic, was divided into 360 degrees, with 30 degrees allotted to each of the 12 signs. The signs were named based on the constellation that fell within them during that period.

In the above diagram, AB represents the path of the celestial equator, while the ecliptic is shown inclined with the signs of the zodiac. In the center is the Earth with e-e marking the equator and f-f on the same plane as the ecliptic. In the tropical zodiac — the zodiac based on the seasons in the Northern Hemisphere — 0 degrees of Aries marks the location of the Sun when the length of the day equals the length of the night, thus serving as a point that signified the return of the power of the Sun as it climbs northward on the ecliptic. Occurring around March 21 each year, this event is known as the vernal equinox and marks the beginning of spring.

As the Sun progresses through Aries, Taurus, and Gemini, the days become increasingly longer. The Sun reaches the northernmost part of the ecliptic at 0 degrees of Cancer around June 21 each year. This marks the summer solstice, the longest day of the year. The Earth stores heat during summer and the hottest temperatures are reached when the Sun is in Leo.

The earth revolving around the Sun and the four seasons.
A diagram of the Earth’s orbit around the Sun in a solar year showing the changing seasons.

From Cancer onwards, the Sun moves southward along the ecliptic, with the length of the day decreasing. Once the Sun reaches Libra the length of the day becomes equal to the length of the night, marking the autumn equinox at around September 21 each year. The days then become increasingly shorter as the Sun moves through the autumn signs of Libra, Scorpio, and Sagittarius.

The winter solstice occurs at 0 degrees of Capricorn around December 21 each year, marking the shortest day of the year and the beginning of the winter. The Sun metaphorically dies and then begins its northward climb steadily through the winter signs of Capricorn, Aquarius, and Pisces, until it reaches the spring equinox to repeat the cycle.

Note that the ecliptic intersects the celestial equator at the two equinoctial points, 0 degrees of Aries and 0 degrees of Libra. The solstitial signs are Cancer and Capricorn. These four cardinal signs represent the beginning of the four seasons of the year: spring, summer, autumn, and winter.


From Lesson 1 – The Birth Chart – The ‘Beginning Traditional Natal Astrology’ Course

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