How We Compute Your Chart

Most astrology sites interpolate positions from pre-computed tables — or copy each other's. GuidingDragon computes the sky from first principles, every time.

The astronomy

Planetary positions come from VSOP87 (Variations Séculaires des Orbites Planétaires), the semi-analytic planetary theory developed at the Bureau des Longitudes in Paris — the same solution used by professional planetarium software. We evaluate the full periodic series for each planet's heliocentric position, then transform to the geocentric, Earth-centred frame a birth chart requires. Retrograde motion falls out of that transformation naturally: it is a geocentric effect, and it's why our station times are computed rather than transcribed.

Lunar positions, phases, and eclipses use the algorithms of Jean Meeus' Astronomical Algorithms — the standard reference for high-accuracy positional astronomy — including ΔT corrections to convert dynamical time to the UTC clock time we publish.

House cusps are computed with the Placidus system from your birth time and coordinates, via local sidereal time.

Why it matters

At the precision astrology works with — a planet's degree and minute within a sign, a house cusp shifting with four minutes of birth-time error — sloppy source data compounds. An ascendant off by a degree can move your rising sign; a mistimed station can put "mercury retrograde" on the wrong day. Computing from ephemeris-grade theory means the chart you read here is the sky as it actually was.

The interpretation

Astronomy gives us where everything is; interpretation is a craft. GuidingDragon weaves five traditions — astrology, tarot, numerology, human design, and life-path work — with AI assistance grounded in your computed chart, never in generic sun-sign boilerplate. Every personalized report starts from your exact birth moment's data and is written for you alone.

Explore: the transit calendar · personalized reports · your free birth chart.