In development · not yet released
Every chart comes with a receipt.
Ephemeris Lab is a professional astrology desktop app for Windows, macOS and Linux. It calculates offline, states exactly how it got every number, and refuses to guess when it doesn't know. One one-time licence will cover all three desktops — no subscription, no account, no cloud.
What we promise
Four things, in writing.
Your licence never expires and never becomes a subscription
You buy a version, you own that version. Not a seat, not a term, not a plan that can be repriced under you later.
No generative AI, ever
No AI readings, no machine-written delineations, nothing dressed up as insight. This is a calculation and consultation tool for people who read charts themselves.
Unlimited charts
No per-chart pricing, no monthly caps, no metering. Your library is a folder of your own files on your own disk.
It states its calculation method on every chart
Zodiac, ayanamsa, house system, node type, ephemeris kernel, engine version, orb policy. On the chart, in the print, in the export.
Provenance
Show a client exactly how the chart was cast.
Every result Ephemeris Lab produces carries the identity of the planetary ephemeris kernel it came from, the engine version that ran it, and the policy identifiers in force — which house system, which zodiac, which ayanamsa, which orbs, true node or mean.
Charts print with an optional provenance page. Search reports carry their disclosures with them. And because the same inputs always produce byte-identical results, a chart you cast today can be reproduced exactly, by you, years from now.
Why this matters
Two programs can hand you two different Ascendants for the same birth and neither will tell you why. Usually it's a house system, a node type, an ayanamsa, or a time zone applied differently — but you can only find that out if the software says what it did.
Birth data
No fake noon charts. No silently guessed time zones.
Unknown time stays unknown
When the birth time isn't known, Ephemeris Lab shows the positions it can stand behind and leaves out houses and angles — rather than casting a 12:00 noon chart and letting an Ascendant look like a fact.
Clock changes are surfaced, not assumed
Enter the time as it was read off the wall clock. The on-disk atlas resolves place to time zone with historical daylight-saving rules. When a moment is ambiguous or never existed, you see both candidates and you decide — the software doesn't quietly pick one.
If it can't calculate it, it says so
Koch and Placidus houses genuinely have no solution inside the polar circle. Ephemeris Lab names that on the page and offers a system that does work there. It never silently substitutes a different house system and labels it with the one you asked for.
Ownership
One licence. Three desktops. Nothing phoning home.
- Windows, macOS and Linux from a single one-time purchase — not three products, not three prices.
- Fully offline. The planetary ephemeris kernels, the world atlas and the time-zone history all live on your disk. Charts calculate on a plane, in a basement, with the Wi-Fi off.
- No account. Licence keys install and verify without signing in to anything.
- No telemetry. No usage analytics, no crash beacons, no "anonymous" statistics.
- Your charts come with you. Import native Solar Fire and Astro Gold chart files and AAF interchange files, with preview and duplicate flagging before anything lands in your library.
- Your library is yours. Whole-library export and import, backup and restore, every save versioned.
- A real desktop app. Native menus, keyboard shortcuts, a command palette, tabs, session restore — not a web page in a window.
Honest about the edges
What it deliberately does not do.
A tool that claims everything is hard to trust on anything. At launch, Ephemeris Lab will not have:
- Astrocartography or locality maps. A relocated natal chart is included; the map is not. It is first on the roadmap that founding customers get to order.
- Written interpretations. No cookbook delineations, no "your Moon in Scorpio means", no AI readings — by design.
- Rectification tooling. Not in version one.
- Vedic layouts, nakshatras or dashas; Chinese astrology; Human Design; draconic charts. Sidereal zodiacs are supported and done properly; Vedic chart formats are a different product.
- Mobile apps, cloud sync, accounts or subscriptions.
Coming: the Founder's licence
Ephemeris Lab is in development and not yet on sale. At launch there will be a 60-day Founder's window at a reduced one-time price, with a price-locked upgrade to version two, first access to builds, and a vote on the order of the roadmap.