Free Solar Arc Directions Calculator
Solar arc directions move your whole birth chart forward at one steady rate — roughly a degree a year — so the years that matter are the ones where a moved planet lands on an original one. This calculator finds those contacts, tells you the month each one becomes exact, and shows the directed chart they come from.How it works ↓
Calculating your placements…
Solar arc directions move every planet, angle and point in your natal chart forward by the same amount — the distance the Sun has travelled by secondary progression since you were born. That works out at roughly one degree per year of life, so at 40 your whole chart has advanced about 40 degrees, intact and in formation.
Why solar arc works where progressions stall
That single mechanic is the reason the technique exists. In secondary progressions each body moves at its own natural speed, which is fine for the Moon and useless for everything beyond Mars: progressed Pluto covers a fraction of a degree in an entire lifetime and will never reach anything. Solar arc gives every planet the same engine. Directed Pluto, Neptune and Saturn all move a degree a year, which means the slow outer planets can actually arrive somewhere in the years you are alive.
How solar arc timing works: one degree, one year
Because the arc is uniform, timing becomes arithmetic. One degree is about one year, so half a degree is roughly six months and a tenth of a degree is a matter of weeks. Practitioners work with tight orbs for exactly this reason — a one-degree orb is a one-year window, and anything wider stops being a prediction and starts being a horoscope.
The contacts that matter: directed planets on natal angles
The hits that matter most are directed planets reaching natal angles, and directed angles reaching natal planets. Directed Saturn arriving at the Midheaven, directed Uranus at the Ascendant: these are once-in-a-lifetime contacts, not the repeating traffic of transits.
A transit from Saturn will cross your Midheaven three times in a year through retrograde motion and then be gone for 29 years. A solar arc contact happens once, builds slowly, and does not come back.
Which aspects solar arc directions use
Most work is done with conjunctions, oppositions and squares. Solar arc is not a subtle technique and it does not reward wide, gentle aspects — the tradition that developed it, largely through twentieth-century cosmobiology, treated the hard angles as the ones that correspond to events.
Why one degree per year is only an approximation
The one-degree-per-year rule is a convenience, not a constant. The Sun's actual daily motion varies between about 0.953 and 1.019 degrees depending on where Earth is in its orbit, so someone born in early January carries a slightly larger arc per year than someone born in July. Over a long life that difference accumulates into real timing error. This calculator uses your real solar motion rather than a flat degree.
Birth time, angles, and when to trust the result
Any solar arc contact involving the Ascendant, Midheaven or house cusps depends entirely on your birth time. Four minutes of error moves the angles a full degree, which is a whole year of timing.
If your birth time is uncertain, the planet-to-planet directions still hold — the angles do not. Read the planetary contacts and set the angular ones aside rather than working from a rectified guess.
Frequently Asked Questions
How is solar arc different from secondary progressions?
Secondary progressions move each planet at its own natural daily speed advanced to years; solar arc moves every planet by the identical arc the Sun has traveled, giving cleaner, more evenly-spaced timing for major events.