Astronomy what was really there

Planet positions are computed with Astronomy Engine (VSOP87, IAU precession and nutation) for the exact UTC instant of birth. The 8,920 background stars and 68 fixed stars are real Hipparcos/HYG catalogue entries, moved by their measured proper motion to the birth year and precessed to the equinox of date.

The Birth Sky view shows true directions from the birthplace. The ground is translucent so you can see what was below the horizon.

Tradition what astrology reads into it

Signs, houses, aspects, rulerships and fixed-star "natures" are conventions of Western astrology. They are shown with the rule that produced them, but they are symbolic: no physical force or statistically established effect is implied.

The Natal Wheel and Connections views are schematic. Lines are information, not beams.

Three things that surprise people

• Tropical signs are ~24° out of step with the constellations of the same name, because of precession.
• A "conjunction" with a fixed star is usually measured in longitude only. Sirius can be "conjunct" a planet while 40° away on the sky. The Stars tab shows both numbers.
• Houses depend on the birth minute: the Ascendant moves about 1° every 4 minutes.

Controls

• Drag to rotate, scroll or pinch to zoom, right-drag to pan.
• Click a planet to light up its network. Click empty space to clear.
• Hover anything (or tap ⓘ on touch screens) for an explanation.
• 1 2 3 switch modes · Esc clears the selection.