Frequently asked questions

Is it free?

Yes. Computing the chart and building the prompt runs for free right in your browser. The interpretation itself is then written by your chosen AI in your own account — subject to its terms and limits.

Which AI should I use?

Any. For Claude and Perplexity the prompt pre-fills directly; the others (ChatGPT, Grok, Le Chat, Gemini, Meta AI, Copilot, DeepSeek) copy the prompt and open their page — just paste it.

Do I have to enter a name?

No, the name is optional. The prompt is also anonymous by default — the name is included only if you turn off anonymization.

Do I have to enter the birth time?

No, but the reading is much better with it. Without the time there are no houses or ASC/MC axes and the Moon's position is only approximate — so the interpretation is more general and less accurate (it misses house-related themes in particular). If you know the time, definitely enter it.

What can it do besides the natal chart?

A relationship chart (synastry), an annual chart (solar return) for a chosen year, transits to the natal chart at any moment, and a chart of a specific moment.

How accurate is it?

Positions match professional NASA/JPL ephemerides (agreement with Swiss Ephemeris ~1″).

And for historical dates? What about time zones?

The entered time is treated as local civil time at the birthplace and converted to Universal Time using the history of time zones, daylight saving included. Three things are worth knowing about old dates:

Before standard time was introduced (1893 in Germany, 1847 in Britain, mostly after 1900 in Africa and Asia) a country had no single clock — what applied was the local mean time of the place. We compute it from the longitude (four minutes per degree), the same as astrological atlases do; the place field then shows “LMT”.
The zone comes from today's borders. For places that belonged to a different country at the time (Lviv in 1921, Strasbourg in 1900, Königsberg), the legal time may have differed — for dates before 1950 the app says so and shows the offset, so you can check it.
Julian dates. Russia dated in the Julian calendar until 1918, Bulgaria until 1916, Greece until 1923 — a date from an old record has to be converted to the Gregorian calendar first (a 12–13 day difference). The app warns about this for those countries and dates.

Two more details: anyone born in the hour that daylight saving skipped — or repeated — has an ambiguous time (we take the first occurrence). And records from the 17th–18th century were kept by sundial, i.e. in apparent solar time, which differs from mean time by up to 16 minutes.

Is my data safe?

Yes. Everything is computed in your browser; nothing goes to a server. The date, time and place are never included in the prompt; the name only if you turn off anonymization yourself.

Can I install it as an app?

Yes, it's a PWA — choose “Install” in your browser. After the first load it also works offline.

Where does the example people's data come from, and how reliable is it?

There are two kinds of examples: real people in the profile picker (each with a note saying where the birth time comes from and how reliable it is) and historical moments in the Events mode (the Apollo 11 landing, 17 November 1989), whose times are documented in ordinary sources. Made-up people were removed from the examples — nothing about their chart can be verified.

Dates and places of birth of well-known people are easy to look up. The weak spot is the time: the Ascendant moves a full degree every four minutes, so a 20-minute error already reshuffles the houses and sometimes the rising sign itself. Astrological databases (Astro-Databank being the best known) therefore grade time quality on the Rodden scale:

AA: birth certificate or civil register — the most reliable.
A: quoted by the person, family or a friend (from memory).
B: from a biography or memoirs — can be off by tens of minutes.
C: no source given — treat with caution.
DD: conflicting data from several sources.
X: date known, time not.

For our examples: Queen Victoria — quality AA, the 4:15 time rests on the official certificate signed at the birth by the Privy Councillors present. Albert Einstein — quality AA, 11:30 from the birth record. Prince Albert — quality B only, the 6:00 time comes from a biography, so his chart shows nicely what an uncertain time means. Victoria and Albert are in the list as a couple on purpose — their marriage is a textbook case of great love, so you can try a relationship chart on them.

We don't use birth data of living people in the examples.

Which years are supported?

From 15 October 1582 (the first day of the Gregorian calendar) to 31 December 2099. Ephemeris data is downloaded in 25-year chunks, so only what the entered date needs is fetched.