‘Astrological Chart Calculations’ preserves and teaches the methods of the most basic astrological chart calculations and tells the story of its history. It addresses the disconnection between the actual process of mapping the sky and the arithmetic that is required to calculate a horoscope, a process required by some astrological certification exams.

It presents the key concepts behind the celestial sphere, the keeping of time, the development of trigonometry and the nature of house systems. It is a general reference useful to any student of astrology, and anyone who has a reasonable grasp of algebra and geometry should be able to follow the explanations and worked calculations. It is hoped that a deeper knowledge of this traditional art of astrology, that is the challenge of mapping the sky and the mathematics of preparing a chart, will allow students to glean not only deeper insights into the subject, but also a unique contact with astrology’s long history.