Astrology as a Source
Sidereal and Tropical Zodiac
A few explanations about the differences of the two astrological systems.
If someone is born on July 1, in the West it is assumed that this persons sun sign is Cancer. According to the sidereal zodiac, however, the Sun is still in the sign of Gemini at that time.
In both systems, the ecliptic (the plane on which the earth orbits the sun, or in other words, the sun‘s orbit) is divided into twelve signs. The ecliptic is a strip of sky in which the Sun and all the planets relevant in astrology move and the constellations are located.
The celestial equator (Earth‘s equator projected into the universe) intersects the ecliptic at two points. These points are the vernal point and the autumnal point. Thus, the points of the equinox.
In the tropical zodiac, it is said that the vernal equinox also marks the beginning of the zodiac sign Aries. Thus, a relationship of the Earth to the Sun is represented. The sidereal zodiac is based on the fixed, or sidereal constellations.
The beginning of the sidereal zodiac was determined in ancient times on the basis of various fixed stars. The distance from the vernal equinox to the sidereal 0 degree Aries is called Ayanamsha.
Since the Earth has an inclination of 23.27 degrees to the ecliptic plane, it describes a kind of gyroscopic motion around the ecliptic pole. The equator (and therefore the vernal equinox) moves very slowly (a complete rotation of the Earth‘s axis takes 25,770 years) backwards through the constellations on the ecliptic plane. This movement is called precession. Precession is accounted for in the sidereal zodiac.
About 1,600 years ago, the vernal equinox and the sidereal beginning of the constellation Aries were in approximately the same place. Nowadays, they are about 23 degrees apart.
The sidereal system is used in Vedic astrology and also by some Western astrologers. In the meantime I prefer to work sidereal, because I find the statements more comprehensive and more accurate.
In a few words, an explanation of the applicability of the two systems could be, for example, as follows: In the sidereal zodiac our BEING as an eternal being shines through more clearly. The sign placement in the tropical zodiac (relationship of sun to earth) expresses more clearly our conditioning and efforts to adapt to the circumstances of this incarnation.
I work mainly with techniques of Vedic astrology.