What is Astrology

ASTRONOMY is the science that deals with the physical phenomena of heavenly bodies, their constition, motion, attraction and resultant manifestations which are perceptible to physical eye. The eclise, the new moon and the full moon are illustrations in point. 
ASTROLOGY  is that part of Astronomy Science which studies the influnace of those heavenly bodies( the Planets & the Stars) on human life and affairs connected with it. It is a science in the sense that its whole edifice is built on scientific data. It is an art in the sense that man interprets the infuence of these bodies on life.
After much debates on the question whether the stars have any influnace at all on human life, the conclusion is that the heavenly bodies do exert a considerable influence on life in this world. Not only that, they give us an inkling as to the nature of our past as well as future.
Like many other things the systems by which the ancients predicted events both in India & west look Different. But it is worthy of note that the fundamentals of both the systems are identical & the results are almost same. It matters little therefore which system is followed.