Every Planet Moves 1° Per Year
Solar arc directions (SADs) work by advancing every planet and sensitive point in the natal chart by the same arc as the progressed Sun — approximately 1° per year. Unlike secondary progressions (where each planet moves at its own rate), solar arcs move everything in lockstep. This creates a map of the entire chart's symbolic development in unison. Solar arcs are widely regarded as the most reliable predictive timing system in modern Western astrology for identifying years of major life change.
Solar Arc vs Secondary Progressions
| Method | Movement Rate | Focus |
|---|---|---|
| Secondary Progressions | Each planet at its own speed | Inner psychological growth |
| Solar Arc Directions | All planets ~1°/year in lockstep | Outer and inner life events |
Reading Solar Arcs
When a solar arc planet conjoins, opposes, or squares a natal planet or angle, a major life event or development typically coincides — often within 1 year of exact. Solar arc Sun conjunct Ascendant marks major identity emergence. Solar arc Saturn conjunct natal Sun describes a year of significant responsibility and reckoning. Use an orb of 1° (before or after exact) for timing reliability. Combine solar arcs with outer-planet transits — when both activate the same natal point in the same year, the period is particularly significant.