Swiss Ephemeris is a software library and ephemeris system used to calculate astronomical positions for astrology software. It is developed by Astrodienst and based largely on NASA JPL planetary and lunar ephemerides. Ava Lux uses it as the calculation layer, not as evidence that astrology itself is scientifically validated.
What is an ephemeris?
An ephemeris gives the calculated positions of celestial bodies across time. Before software, astrologers worked from printed ephemeris tables. Modern software computes the positions directly.
What Swiss Ephemeris is built from
Astrodienst describes Swiss Ephemeris as a high-precision ephemeris based largely on NASA Jet Propulsion Laboratory planetary and lunar data. In 2026 its current information notes support for newer JPL DE441 material as well as the long-standing DE431 framework.
What it can calculate
- Planetary and lunar positions.
- Lunar and planetary nodes and apsides.
- House cusps and angles for supported house systems.
- Asteroids and additional bodies, depending on the implementation.
- Sidereal and tropical coordinate options.
Precision in calculation does not equal proof of interpretation
This distinction is essential. Swiss Ephemeris can tell us where Mars was with extremely high astronomical precision. It cannot scientifically prove that Mars in a particular house means a specific psychological pattern. The first statement is calculation; the second is astrology.
Why Ava Lux uses it
If a symbolic reading is going to begin from planetary positions, those positions should at least be calculated correctly. Ava Lux therefore uses a professional astronomical engine for the sky map before adding any Kabbalistic or interpretive layer.
What birth data enters the calculation?
Date, time and location are converted into the time and geographic inputs required to calculate the local chart. Exact time becomes especially important for the Ascendant, Midheaven and houses.
Sources and textual boundary
Ava Lux editorial rule: source texts, later Kabbalistic interpretation, modern astrology and the Ava Lux reading method are not treated as if they were the same layer. Where traditions disagree or textual versions vary, the page says so.