Classical & Hellenistic astrology
One deterministic engine runs the whole chart, weighing your placements against 2,373 classical conditions and computing every verdict from real geometry, each one named to the placement it rests on. The same engine reads compatibility twelve ways, marriage to business to mentor, each bond scored over real contacts, not sun signs. And the optional personal astrologer works only from what the engine computed: with no chart of its own it has nothing to invent from, cites the tradition by chapter, and withholds any answer it can't ground in your placements, at no cost. Your first reading is free.
The browser version is the free tier: the chart, the wheel, the dignities and your first reading. The full synthesis engine and the personal astrologer are unlocked on Google Play, for now.
What readers say
Real responses to birth-chart readings cast by the app, posted in astrology communities and sent by message. Not one was asked for. See the readings & their sources ↗
Extremely accurate astrology app, probably because it’s based on astronomy and math… The biggest strength in my opinion is the depth and details in every feature, specially the forecast reports.
samerquintanaGoogle Play review · Aug 2026
View on Google Play ↗I need a minute to let this sink in, but I wanted to thank you first. It's spot on. Holy smokes. You're good!
ShinyPineapple7755Observational Astrology community
View on Facebook ↗This quickly became my favorite astrology app! So insightful and full of knowledge to interpret your birth chart!
MeraiahGoogle Play review · Aug 2026
View on Google Play ↗This resonates greatly with my lived experience. I appreciate the tone of the reading and the information provided. I have no problem with using AI. I will follow up and check out your app.
Jani M.Observational Astrology community
View on Facebook ↗thank u so much for spending time to tell me about my chart I really appreciate it. It’s quite correct that I do feel things very intensely even when things are not that serious.
SweetPeacock5704Observational Astrology community
View on Facebook ↗WOW! This was so beautifully explained and honestly gave me so much hope and inspiration. Really made me want to shift how I've been seeing everything in my life. I was so lost.
Michaela O.Reader message
Shane St. Pierre’s Classical Astronomy app is a standout tool for anyone interested in understanding the sky as it actually appears from an observer’s perspective. Instead of overwhelming users with abstract models or overly complex astrophysics data, this app brings the focus back to traditional, observational astronomy—the foundational science of celestial tracking that navigators and astronomers used for centuries.
Skyler MoodyGoogle Play review · Aug 2026
View on Google Play ↗This is beautiful and I can really tell that you’ve been studying astrology. … I’ll check go check out the astronomy and astrology app.
Cecilio BonillaObservational Astrology community
View on Facebook ↗Wow, I love how you broke down the inner conflict in the chart. I have lots of contradictory combinations in my chart too. I'll definitely try to find the app you mentioned.
Pamela B.Observational Astrology community
View on Facebook ↗This is goosebumps, as if you read my entire personality. I have known ever since that I am impulsive, but now I know.
GorgeousLychee6510Observational Astrology community
View on Facebook ↗What it computes
Not a modern rewrite of the tradition, but the procedures the Hellenistic astrologers actually practised — sect and the Lots, the rulers of the places, and the time-lords that move the reading through the life. Each is computed for your chart and shown with its result.
The Hellenistic standard. Each sign is one place, counted whole from the rising sign.
Read the doctrine →Day chart or night chart, the first judgement, setting which planets ease the life and which press on it.
Read the doctrine →Worksheet ↓Domicile, exaltation, the sect-based triplicity lords, bound and decan, scored for every planet.
Read the doctrine → IVThe Egyptian term rulers, degree by degree, for the finer grade of judgement.
Read the doctrine →The body and the daimon, computed by sect, with Eros and the rest, read like a second Ascendant.
Read the doctrine →Worksheet ↓The lord of the year, found by counting places from the Ascendant, the simplest of the time-lords.
Read the doctrine →Worksheet ↓Releasing the times from Fortune and Spirit, the peak periods and the loosing of the bond, from Valens.
Read the doctrine →Worksheet ↓The apheta and the anareta, directed by the daily turning, one equatorial degree to the year, the oldest timing measure.
Read the doctrine → IXConjunction, sextile, square, trine and opposition, by whole sign, weighed as the tradition weighs them.
Read the doctrine → ✦ The methodThe nine techniques above are the parts. This is how they combine into one timing reading: what your chart promises, which time-lords activate it, and when a promised thing ripens.
Learn how to use the Timelord's Toolkit →The nine doctrine pages above, each worked in full on a real chart. Or read the whole tradition as a three-part survey at Learn classical astrology, taught from the sources.
What you get
A personal Hellenistic astrologer, a full natal reading, relationship synastry, and the living sky. The same computed positions feed every one of them.
Ask anything about your chart. It answers as a classical astrologer would, from a sealed set of facts computed for your birth moment and nothing else. Every claim is checked against your own figures before you read it. Answers in English, Spanish, German, Portuguese and Czech.
Meet the astrologer →The full Hellenistic method, computed live: whole-sign houses and sect, the essential dignities and the triplicity lords, the Lots of Fortune and Spirit, and the time-lords — annual profections, zodiacal releasing and primary directions. Every topic ends in a verdict, with the mechanism stated. Drawn from Valens, Dorotheus, Ptolemy and Paulus.
What the sky means for two people. Twelve bond modes — marriage, friendship, business, mentor, family and more — each scored to a single verdict band, grounded in Tetrabiblos IV.5.
One geocentric engine, four surfaces: a deferent-and-epicycle orrery, a first-person dome over any date and latitude, a walk-in 3D theatre, and an augmented-reality overlay on your phone's camera.
Why it can be trusted
Traditional astrology is written doctrine, not opinion. Each reading names its source, so you can check it. Ptolemy, Dorotheus, Vettius Valens, Firmicus Maternus and Paulus Alexandrinus, quoted by chapter. A claim the engine cannot source is left out of the reading.
The interpretation is computed, not written by a language model. The same birth data yields the same reading, to the letter, every time. The engine evaluates the doctrine and states the result.
Classical doctrine speaks in its own voice, physical and direct. A separate, clearly labelled modern reading follows for those who want it. The two are never blended, so you always know which tradition you are reading.
Relationship astrology, rebuilt
Most apps lay two Sun-signs side by side and call it compatibility. This one reads the relationship itself: both charts weighed through a five-phase Hellenistic engine across twelve bond modes, from marriage to business to mentor. Each bond is scored to a single honest verdict on a transparent Bond Index, and every step that produced it is shown.
Eclipses & the mundane sky
The oldest astrology read eclipses as the heaviest of omens — turning-points for kings and countries, and for a person when the darkened luminary falls on a sensitive degree of the birth chart.
A solar or lunar eclipse near a natal planet, an angle, or a Lot is felt across months, not the hour it darkens. It passes a quiet degree unfelt; but on the ruler of a profected year, on the degree of the Ascendant, or on the Lot of Spirit, it marks a hinge — a matter begun, ended, or brought suddenly to light. What it brings is read from the planet it eclipses and the place it falls in.
In mundane astrology the same eclipse is a sign for the wider world: the region it shadows — by Ptolemy's geographical triplicities — and the affairs ruled by its sign and the planets configured with it. Public omen and private hinge are read by one doctrine; and because every eclipse belongs to a Saros family that returns every eighteen years, its meaning carries a theme the world, and the native, have met before.
Eclipse interpretation follows Ptolemy, Tetrabiblos II, with Hephaistio. The engine marks which eclipses land on your own chart's degrees, and gives each its classical geography.
"An eclipse on my tenth — what does it mean?"
The coming solar eclipse falls on the ruler of your tenth place — the lord of a year your profection has already turned to standing and vocation. Read it as a hinge in the public life: an office taken up or set down, felt across the season the eclipse governs, not the hour it occurs.
TETRABIBLOS II · AN ECLIPSE ON AN ACTIVATED PLACE
The full catalogue · a separate study
Every eclipse from 3996 BC to AD 3648 — 35,387 of them — located by its place in the repeating pattern rather than by ephemeris: the 18-year team, the Saros and Inex series, and the 649-year Date-Repeating Cycle of J. B. Dimbleby, reconciled to the Saros/Inex lattice with magnitudes by Meeus. Predict from any date, browse them all, and walk the nested cycle ladder.
The founder's story
I did not come to astrology the way most people do. I came to it the way an engineer comes to a claim that annoys him: I wanted to take it apart, so I built the whole of it from first principles and let the machine tell me what was there. Then I ran it against people whose lives are documented, and the trait descriptions kept landing at a rate I could not explain away and stopped trying to. I have no mechanism to offer you, and I will not invent one. What I can do is show you exactly where every statement comes from, so you can check it yourself.
Where to read your chart
The full engine, the interpretation, the wheel and the astrologer. A one-time $19.99 unlock, no subscription: unlimited chart syntheses and unlimited PDF reports, every one grounded in the classical sources. Built for astrologers doing repeated chart work.
Get it on Google PlayThe iOS build is on the way. The same engine, the same doctrine, the same sources.
Coming soonThe classical calculation, the wheel and the full essential dignities, and your first complete reading, at no cost. No account, nothing to buy. The full interpretation, the astrologer, synastry and unlimited PDF reports are in the app.
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Classical Astronomy & Astrology