Difference Between Tropical And Sidereal Zodiac

#sayana_Zodiac, #Niryana_Zodiac, #Western_Astrology. #Astronomy, #Tropical_and_sidereal_Zodiac

"It seems that the sidereal system (Nirayana) was used in astrology with predictive purposes, whereas the tropical system (Sayana) was used in astronomy to observe the equinoxes and solstices." {Dr. S. Madhavan, scientist, astrologer and astrology researcher, in his book, Muddle of Ayanamsa (Controversies around Ayanamsa)}

Sayana / Tropical Zodiac	Nirayana Chakra / Sidereal Zodiac
Western Astrology	Vedic Astrology
It uses the Vernal Equinox as the point of reference	It uses the Sidereal Zodiac (Nirayana chakra), which adopts a fixed star as the point of reference.
It fix the Vernal Equinox as 0° Aries regardless of whether the Sun is actually observed against the backdrop of the stars in the constellation of Aries on that particular day & year.	It establishes the planetary position against the backdrop of the fixed stars so that real-time observation matches the chart positions.
A zodiac determined by the equinoxes and solstices instead of the actual star positions of the constellations. The date of the equinoxes establishes 0°Aries & 0° Cancer, whereas the solstices establish 0° Cancer & Capricorn.	A zodiac that is based on the actual constellations in the sky along the ecliptic and follows the astronomical precession of the equinoxes.
The tropical zodiac is generally associated with Western astrology.	The sidereal zodiac is generally associated with Eastern or Vedic astrology.

The reason for the discrepancy between these two systems is that there is a "wobble" in the rotation of the earth on its axis. As a result, the Sun does not return exactly to the same point of 0° Aries each spring at the vernal equinox as observed from a fixed star. It misses by a tiny amount (around 50” of arc according to the most widely used reference point). This may not seem to matter much, but when it accumulates over the years, the vernal equinox is seen to slip back and back into the sign of Pisces then eventually Aquarius and so on. This phenomenon is known as precession of the Vernal Equinox.

At the present time, the discrepancy between these two systems is about 24°. This ever-increasing difference is known as the Ayanamsa (moving part). If you subtract the daily specific Ayanamsa from the planet's position in a Western tropical chart, you will get its location in the Vedic Sidereal Chart.