About Moon and Rising

The engine

Planet positions come from astronomy-engine, an open-source library of published astronomical models. House cusps, the lunar nodes and Black Moon Lilith are computed in-house from the formulas in Jean Meeus's Astronomical Algorithms, and Chiron from a table of NASA JPL Horizons data.

What checks it

• NASA JPL Horizons, for the Sun, the Moon, the planets and Chiron.
• NASA's Five Millennium Canon of Solar and Lunar Eclipses (Espenak and Meeus).
• The U.S. Naval Observatory's published equinoxes and solstices.
• A second, independent ephemeris: we compare our house cusps, sign changes, stations and Ascendants with its outputs.

Each comparison is an automated test with a tolerance set before the first comparison. A page prints a time only as precisely as its test supports, usually to the minute.

• 3′Planet positions agree with NASA JPL Horizons to within 3 arcminutes in our tests.
• 0.2°House cusps and the Ascendant agree with an independent ephemeris to within 0.2° in our tests.
• 21 sAll 24,251 Moon sign changes from 1900 to 2050 agree with an independent ephemeris to within 21 seconds.

House systems

Charts default to Placidus, the system most reference sites use, and you can switch to Whole Sign, Equal, Koch or Porphyry on the chart itself. Every chart names the system it uses. Above 66.5° latitude Placidus and Koch break down, so those charts switch to Whole Sign and say so. No house system is the real one: they are different conventions for dividing the sky.

Why houses differ between house systems

How the readings are written

Our interpretive text is drafted with software assistance, then checked by fixed rules: the astrological facts it states, and things it must never say, such as predictions of illness, doom or how a relationship will end. What happens next depends on the kind of page, and each page's own note says which.

• Birth-chart sign readings, the planet-in-sign pages, and the Moon and rising sign readings: read and edited in full by our writers before publication.
• The opening of the birth-chart reading (the Sun–Moon blend and the leading element and modality): checked against our voice guidelines by an automated reviewer before publication; no person reads each one.
• The planets-in-houses block of the birth-chart reading: checked against our voice guidelines by an automated reviewer before publication; no person reads each one.
• The aspects block of the birth-chart reading: checked against our voice guidelines by an automated reviewer before publication; no person reads each one.
• The house block of the Saturn return calculator: checked against our voice guidelines by an automated reviewer before publication; no person reads each one.
• The copy block of the transits calculator: checked against our voice guidelines by an automated reviewer before publication; no person reads each one.
• Moon, retrograde and eclipse pages: checked against our voice guidelines by an automated reviewer before publication; no person reads each one.
• Sign-pair compatibility pages and the synastry calculator: checked against our voice guidelines by an automated reviewer before publication; no person reads each one.
• The guides (long-form articles): read and edited in full by our writers before publication.

Astrology is a symbolic language

Controlled studies have not found that astrological placements predict personality or relationships, and we don't claim they do. We treat a chart as a vocabulary for reflection: we're exact about where the planets were, and honest that what they mean is interpretation.

Corrections

If you find a mistake, such as a wrong time or position or a reading that says something it shouldn't, write to hello@moonandrising.com. We check it against our sources and fix it. When the engine was wrong, the fix reaches every page it feeds.

Contact

General questions: hello@moonandrising.com. Privacy questions and deletion requests: privacy@moonandrising.com, as the privacy policy explains.

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