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…
Your birth chart drifts forward as you age. Everything moves at once and by the same amount: planets, Ascendant, Midheaven, all of it. The pattern never distorts, it just slides. The rate is roughly one degree a year.
The years worth knowing about are the ones where something slides onto something else. Solar arc directions find those years, and because the drift is steady, distance is time. One degree of gap is about one year of waiting.
What a solar arc hit actually looks like
One contact, once, and then never again in your life.
Directed Saturn reaches your Midheaven and a career takes a structural turn: a promotion that arrives with weight, or a job that ends. Directed Uranus reaches your Ascendant and something about how you live or present breaks open. These are not moods that pass in a fortnight. They build for a year or so, land, and are gone for good.
That is the appeal, and also the catch. A transit from Saturn crosses your Midheaven three times in one year as it stations and turns, then comes back in 29 years. A solar arc contact gets one attempt. If you know the year, you know it is the only one.
How to read the dates yourself
Because everything moves at the same steady rate, you can do this by eye once you know the trick.
Find two points in your chart, say Saturn and your Midheaven, and count the degrees between them. That number is roughly the number of years until they meet. Saturn sitting 12 degrees behind your Midheaven means the contact lands somewhere around age 12. Forty degrees means around 40.
Half a degree is about six months. A tenth of a degree is a few weeks. This is why practitioners work with such tight orbs here: a one-degree orb is not a measure of strength, it is a one-year window. Anything wider stops being a date and starts being a horoscope.
The calculator does the arithmetic properly, but being able to estimate it in your head is what makes the technique usable in conversation.
Why the slow planets finally do something
This is the problem solar arc was built to solve.
Secondary progressions move each planet at its own natural speed. That works beautifully for the Moon, which covers about a degree a month, and is useless for everything past Mars. Progressed Pluto travels a fraction of a degree in an entire lifetime, so it never arrives anywhere and can never tell you about a year.
Solar arc gives every planet the same engine. Directed Pluto, Neptune and Saturn all move a degree a year, the same as everything else. Suddenly the heavy, slow, life-restructuring planets can actually reach your angles inside a human lifespan. That is why the technique exists.
Which contacts count
Conjunctions first, then oppositions and squares. Solar arc came out of twentieth-century cosmobiology, a tradition that worked almost entirely with hard angles because those are the ones that showed up as events. Some practitioners read sextiles and trines; most treat them as secondary.
The contacts carrying the most weight involve the angles: a directed planet reaching your natal Midheaven or Ascendant, or your directed Midheaven or Ascendant reaching a natal planet. Those tend to be the legible ones afterwards, the year someone points at and says that is when it changed.
Summer births run slow
One degree a year is a rule of thumb, not a constant, and the difference is bigger than it sounds.
Earth moves faster through its orbit in January than in July, so the Sun appears to move faster too, between about 0.953 and 1.019 degrees a day depending on the time of year. Under solar arc, a day of that motion stands in for a year of life.
In practice, a chart born in early January runs slightly fast and one born in high summer runs slow. By age 30 that gap is worth roughly a year of timing. Predict a July birth with a flat degree and you can be a full year early. This calculator uses your real solar motion instead.
When you can trust the result
Everything above depends on your birth time, and specifically on the angles.
The Ascendant and Midheaven move about a degree every four minutes of clock time. Under a technique where a degree is a year, a four-minute error in your birth time is a one-year error in your prediction. A rounded-off or half-remembered birth time produces dates that look precise and are not.
If your birth time is solid, read the angle contacts first, because they are the best thing this technique does. If it is uncertain or unknown, read the planet-to-planet contacts, which hold regardless, and leave the angles alone rather than working from a guess. Guessing is how you end up confidently wrong about a year.
A real example
Princess Diana: Death in Paris, August 31, 1997.
Directed lilith reached an exact square to the natal ascendant on August 30, 1997, orb 0°00'.
That's 1 days from the event itself. It's computed from real birth data, not fitted to it.
Frequently Asked Questions
What is a solar arc direction in astrology?
A predictive technique that moves your entire birth chart forward at one steady rate, about a degree per year, then reads the years where a moved point lands on an original one. It is called a direction rather than a progression because everything travels together instead of at its own speed.
How is solar arc different from a transit?
A transit is where a planet actually is in the sky today. Solar arc is a symbolic movement of your own chart. The practical difference is repetition: transiting Saturn crosses a point three times in a year and returns 29 years later, while a solar arc contact happens once in your life and does not come back.
Do I need my exact birth time for solar arc directions?
For contacts involving the Ascendant or Midheaven, yes, and those are the technique's best contacts. The angles shift about a degree every four minutes, and a degree is a year, so a four-minute error is a year-wide miss. Planet-to-planet contacts hold fine without a birth time.
Can solar arc directions run backwards?
Yes. Converse directions move the chart backwards by the same arc, and some practitioners use them for the past or for inherited patterns. Forward directions are the standard method and what this calculator computes.
Where can I read more about solar arc directions?
Noel Tyl's Solar Arcs (Llewellyn, 2001) is the standard modern reference and the source most practitioners work from. Reinhold Ebertin's earlier cosmobiology writing is where the hard-aspect approach originates.