Western & Vedic Astrology
Vedic Astrology is the mother of all branches of astrology. History proves that India is the land of occult sciences. The job done by our sages on astrology is unbelievable but we don't have complete literature on that. Our culture is ruled by foreigners approx 800 years and during this span of slave age we have lost most of our things. Astrology was in the hands of scientists and mathematicians before slave age. Vedic astrology is based on 18 rules (siddhants) and each one has its different set of rules. As we know it is not possible to apply all rules. Vedic astrology is based on Niriyan values of Ephemeris which is the most correct and accurate but they do not follow the aspects of planets and houses degree to degree which not much accurate. In Vedic astrology start of the cusp is taken as the mid of the House which gives less accuracy. Some rules of vedic astrology are as it is as before but some are altered time to time by different astrologers for there self purpose.
Western Astrology have taken most of the things from Vedic astrology and after that doing there researches on it. They have taken the same sequence of days as in Vedic. They have also taken the aspects but they have modified them up to the orb of the planet and degree to degree. They follow the Placidus System for division of Cusps which is more accurate. There logical approach keeps them understandable and explanatory. They also fails in there predictions but they work on that further up to the extent of accuracy. They work on Sayan system which is not accurate. They do not consider the inclination of Earth on its axis. They follow Sun signs but vedic follows Moon signs.