The most widely used predictive system in Indian astrology divides a life into planetary periods totalling 120 years, and where you start in the sequence is decided by which nakshatra the Moon was in when you were born.

Each of the nine planetary lords gets a fixed span — Venus twenty years, Saturn nineteen, Mercury seventeen, and so on down to the Sun's six — and the exact degree of the Moon within its nakshatra sets how much of the first period you have already used up. Your whole life map hangs off one lunar position measured to the arcminute.