This is a diagram Johann Kepler made showing the beautiful geometric pattern formed by the cycle of Jupiter & Saturn conjunctions over the course of a millenniuim. Kepler, the brilliant astronomer and mathmatician who solved the age-old problem of planetary motion, was court astrologer to the Holy Roman Emperor, camp astrologer to a famous general, and specialized in astrological weather forecasts.
Notice that Kelper used astrological symbols for the Zodiacal signs, the book cover substitutes their Latin names.