From about the mid-16tth century, with the scientific revolution which marked the point where scientific study moved away from ancient tradition towards what we now see as modern science.Wonder when and why the areas were later became seperate fields.
"By the time of Francis Bacon and the scientific revolution, newly emerging scientific disciplines acquired a method of systematic empirical induction based upon experimental observations.At this point, astrology and astronomy began to diverge; astronomy became one of the central sciences while astrology was increasingly viewed as an occult science or superstition by natural scientists. This separation accelerated through the eighteenth and nineteenth centuries." (Wikipedia)