The differences arise in the way the zodiac is configured. Vedic astrology uses a sidereal (star-based) perspective and tropical astrology uses a seasonal focus.
- The sidereal ecliptic longitude of a celestial body is its longitude on the ecliptic defined with respect to the "fixed" stars
- The tropical ecliptic longitude of a celestial body is its longitude on the ecliptic defined with respect to the vernal equinox point.
Vedic Astrology is frequently called predictive astrology because of its ability to predict events in life. This ability is due to the refinement in the various systems of the science, and requires significant subtlety of understanding and perception on the part of the practitioner.
Vedic Astrology is based on the Sidereal Zodiac as opposed to the Vernal Zodiac of Western Astrology. Vedic/Sidereal Astrology uses the fixed observable stars in the sky whereas Western Astrology is more time based, determining the beginning of the zodiac as corresponding to the start of the Vernal Equinox. In the year 2002, the difference between the two systems is considered to be between 22 and 24 degrees and indicates the difference between the point of the vernal equinox and the first point of the constellation Aries.
We could say the consequence of this difference is a Vedic system which does not give the sun the same prominence that is has in the Western system. While acknowledging the Sun as a significator of the essence, or soul, Vedic Astrology, by following the Sidereal Zodiac gives more relative importance to the influence of the other planets as opposed to making the Sun the focal point.
In Vedic Astrology, the rising sign or ascendant is represented by the sign which is on the eastern horizon at the time of birth and considered to be the most important factor in prediction since it is the most frequently changing aspect of the chart – changing every two hours. It is the most pivotal point from which one considers everything, the context from which all of the planets are evaluated.
In Vedic Astrology more emphasis is placed on the Moon than on the Sun. The moon represents the mind which is seen as a very important factor and consequently is a major determining factor in how one interacts with the world.
Vedic Astrology is also sometimes called constellation astrology because it takes into account fixed stars called constellations. As a result, one considers not only the influence of the planets in a sign but also the subtle influences exercised by the constellations. This means that when a planet passes through a sign, it expresses the influence of the sign and is also tempered by the influence of the constellations of the sign. To practice predictive astrology, one must be able to go deep into the subtle influences of the constellations.Vedic Astrology also employs mathematical divisions called Shadbalas and Shadvargas. They give the precise strength of each planet in a mathematical figure which enables one to understand the real potency of the planets.
Another system of delineation in Vedic Astrology is aspects known as “yogas”. This is a unique system for understanding the power of the associations between the planets in their placement from one another. When the planets have formed yogas, they create specific results which are powerful.The Dasa System (the planetary cycles) is another feature of the Vedic system which indicates a period during which a planet’s influence becomes fully operative. This enables one to give precise predictions during a particular period.
Lastly, the great sages, in their compassionate nature, wanted to help mankind to reduce their miseries, and thus introduced a system of remedies or Upayas, for overcoming suffering from planetary afflictions. These remedies vary depending on the affliction and include japas, meditation, chanting of suitable mantras, fasting and worship.So which is superior, Western or Indian Astrology? My personal answer is overwhelmingly the Indian or Vedic system of astrology. While western astrology has it merits; like for example it is slightly superior in delineating the character or the psychological make up of a person. If; for example; only the Sun Sign were to be taken to determine which astrology is superior; then western astrology will win. My Sun sign by western tropical zodiac is Virgo and I do show many of the Virgo qualities. According to vedic astrology my sun sign is Leo (because of precession of zodiac) which does not correctly reflect Leo or the lion like traits. However from a predictive point of view Hindu astrology is far superior. There is nothing of the equivalent of this in western astrology. Western astrology uses some transits of inner and outer planets to predict which is very inferior and incapable of giving correct predictions. If dasas (planetary periods) have to be used then we cannot use a tropical zodiac. Only a sidereal zodiac which takes into consideration the precession of the equinoxes (called Ayanamsha)