There are two main schools of astrology that use the planets, signs, and houses: Vedic astrology and Western astrology. They are similar, yet different; why is this so and what does it mean?
First of all, the Vedic system uses a constellational way to measure the zodiac; that is, it uses the actual constellations in the sky to mark out the signs of the zodiac. Basically it is more astronomically accurate; it is called the sidereal zodiac. The Western system uses the tropical zodiac, which determines the boundaries of the twelve signs by marking out exact thirty degree sections of the sky starting from the vernal equinox; that is, the exact position of the Sun on the first day of spring.
Sidereal astrology is constellationally based; tropical (western astrology) is seasonally based. This is not a value judgment on one system being better than the other. You could also say that the Vedic-sidereal system is based on the relationship between the earth and the stars, whereas the Western-tropical system is based on the relationship between the Earth and the Sun.
Interpretationally, the Vedic system describes very accurately your acts, your jobs, family, health, etc. and other situations in your life. The Western system describes your mind and psychology: what you think about, your psychological disposition, how you relate to your parents, children, and friends. In short, Vedic astrology describes what you do, Western describes what you think.
A lot of people also ask how can there be two different charts for the same person. This is because in the Vedic you might be a Pisces, but in the Western you are an Aries; which one is right? The only answer I can give there is that these are two different interpretation styles based on two different measuring systems. Theoretically they are equal to each other.
It could be argued that the Vedic system is more accurate simply because it is a system that is relatively intact. The Vedic tradition is from India where spiritual disciplines have not changed in thousands of years. Western culture however has suffered tremendous losses though the ravages of the Dark Ages in Europe, where literacy was very rare and open minded spiritual inquiry was stamped out by the Church for a thousand years. Western astrology carries the baggage of the materialistic "intellectual" culture and is crude compared to the complexity and subtle refinement of the Vedic astrological system.
To find out more about the differences between the Vedic and Western astrological systems go to www.starworldnews.com. There are many articles published on a regular basis using both western and Vedic techniques to better understand current events and trends in the world we live in.