Purposes of astrology The original purpose of astrology, on the other hand,was to inform the individual of the course of his life on the basis of the positions of the planets and of the zodiacal signs (the 12 astrological constellations) at the moment of his birth or conception. From this science,called genethlialogy (casting nativities),were developed the fundamental techniques of astrology. The main subdivisions of astrology that developed after genethlialogy are general,catarchic,and interrogatory. General astrology studies the relationship of the significant celestial moments (e.g.,the times of vernal equinoxes,eclipses,or planetary conjunctions) to social groups,nations,or all of humanity. It answers,by astrological means,questions formerly posed in Mesopotamia to the bāru.Catarchic (pertaining to beginnings or sources) astrology determines whether or not a chosen moment is astrologically conducive to the success of a course of action begun in it. Basically in confl