In astrology, there are two main systemsused to define the zodiac: the tropical zodiac and the sidereal zodiac. These systems are used to determine the position of celestial bodies, particularly the Sun, at the time of an individual's birth. While both systems are used to interpret astrological charts, they differ in their approach and calculations.
Here's a detailed explanation of the differences between the tropical and sidereal zodiacs:

Some definitions

Tropical Zodiac: The tropical zodiac isbased on the position of the Sun relative to the Earth's seasons. It divides the ecliptic (the apparent path of the Sun) into twelve equal parts of 30 degrees each. The starting point is the vernal equinox, the moment when the Sun crosses the celestial equator and enters the northern hemisphere.

Sidereal Zodiac: The sidereal zodiac, onthe other hand, is based on the fixed positions of the stars. It divides the ecliptic into twelve unequal parts, known as "signs," based on the constellations that lie along the Sun's path. The starting point is the first point of Aries, which is the intersection between the celestial equator and the ecliptic.

Precession:

Tropical Zodiac: One of the significant differences between the two zodiacs is the consideration of the precession of the equinoxes. Due to the Earth's wobble on its axis, the positions of the equinoxes and solstices gradually shift over time. The tropical zodiac doesn't account for this shift and remains fixed to the seasons. Therefore, the tropical zodiac is not directly aligned with the constellations.

Sidereal Zodiac: The sidereal zodiac takesthe precession into account and adjusts for the gradual shift of the equinoxes. As a result, the sidereal zodiac aligns more closely with the actual positions of the constellations. Over time, there is a slight shift between the tropical and sidereal zodiacs due to precession.

Zodiac Signs:

Tropical Zodiac: In the tropical zodiac,the twelve signs have symbolic meanings associated with the seasons. They are Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, and Pisces. Each sign corresponds to a 30-degree arc along the ecliptic, starting from the vernal equinox. The tropical zodiac is used predominantly in Western astrology.

Sidereal Zodiac: The sidereal zodiac assigns the signs based on the actual constellations. However, due to precession, there is a slight discrepancy between the constellations' positions and the signs of the sidereal zodiac. The sidereal zodiac is primarily used in Vedic or Hindu astrology.

Nakshatras:

Sidereal Zodiac: In addition to the twelve signs, the sidereal zodiac also incorporates a lunar-based system known as nakshatras or lunar mansions. Nakshatras divide the zodiac into 27 equal parts
based on the Moon's position at the time of birth. Each nakshatra has unique qualities and influences the individual's personality and life experiences.

Interpretation and Timing:

Tropical Zodiac: Astrologers using the tropical zodiac focus on the relationship between the planets and the seasons. They analyze the aspects and alignments of the planets within the tropical signs to derive insights into an individual's personality, potential, and life events.

Sidereal Zodiac: Astrologers using thesidereal zodiac emphasize the connection between the planets and the fixed stars. They analyze the positions of the planets in relation to the sidereal signs and nakshatras to interpret an individual's character, destiny, and karmic influences.

It's important to note that the choicebetween the tropical and sidereal zodiacs is a matter of astrological tradition, cultural background, and personal preference. Both systems have their own merits and can provide valuable insights, but they approach astrology from slightly different perspectives due to the different ways they define the zodiac.