The most intriguing and basic difference in Vedic and western Astrology is the use of lunar sign in Vedic system and the sun sign in the western astrology.
This makes the Vedic or Hindu system of astrology to have placement of astronomical bodies coinciding with the astrological settings.
The earth’s equator shifts by nearly 51” backwards among the signs of zodiac, along the longitude every year, a phenomenon termed as “precession of equinoxes”.
The western Astrology starts with the first sign of zodiac Aries at a place where the sun crosses the equator. And this a relatively temporal position where one degree of change occurs every 72 years.
Due to this phenomenon, and use of sun as the determiner of zodiac, the western system of Zodiac even on starting at the same point with Sidereal zodiac has shifted to approximately 23 degree (25 days). The shift is still continuing.
However, in the sidereal or Vedic astrology, the zodiac is aligned with the 27 constellations or fixed star groups.
In this, the first zodiac sign Aries coincides aligns with the first constellation Ashwini . A correction factor for the vernal equinox gets automatically applied.
This makes Vedic astrology interpretations as more reliable and accurate. In fact, the lack of faith in astrology and labeling of astrology a non-scientific concept is due to fact that astronomical positions of planets do not coincide with the theoretical astrologically defined positions.
In Vedic Astrology, the planetary periods called ‘dashas’ render the horoscope highly predictive. The zodiac sign, the house, the house lordship, the aspects, conjunctions, strength of the planet in Vedic dashas give very clear insights and accurate predictions.
Also, mahadasha or major planetary periods are subdivided into 1-3 years sub-periods that make the calculations further simplified and accurate.
It has been observed that Vedic astrology gives a better insight into a person’s karmic accounts and tendencies.
The predictions made on basis of Vedic astrology are more accurate and have less basis of psychological interpretation.
The Vedic chart is square to look while the tropical chart is round in shape.
Many of western Astrologers who studied Vedic astrology later chose to practice their profession using Vedic system of Astrology.