Positions
Sun, Moon and planet positions come from astronomy-engine, a free ephemeris library checked against NASA’s JPL tables. It is the same engine in the app and on this site. Geocentric positions, seen from Earth, as in astrology.
Method
How
we calculate.
Everything this site and the AstroXP app show starts from an astronomical calculation. Here is which one, how precise, and what we don’t claim.
The zodiac
Tropical zodiac: Aries starts at the March equinox. It is not the constellation of the same name, which has drifted about 24° since antiquity; the app explains it, and also shows the real constellation behind your Sun.
The rising sign
It depends on the time to the minute and on the place: it changes sign about every two hours. Without a birth time, AstroXP shows no rising sign rather than a wrong one. Historical time zones (daylight saving, changes of rule) are taken into account.
Houses
Whole-sign houses: each house is one whole sign, starting from the rising sign. It is the oldest and most readable system; it doesn’t depend on latitude.
Degrees
A degree is truncated, never rounded: 29.96° Taurus is written 29°57′ Taurus, not “30°”, which would already be Gemini.
The texts
Every sentence must be able to be wrong for someone else: otherwise it says nothing. AstroXP’s readings start from the calculated positions; the AI that writes them is given the real aspects and houses and is not allowed to invent any.
What we don’t claim
Astrology has no proven predictive value. AstroXP is an entertainment and self-knowledge app: it describes an exact sky, it doesn’t decide anything for you.