The Big Picture
Your birth data travels through three stages before becoming a verified planetary position.
01
Your Birth Data
Date, time & place
→
02
Our Engine
VSOP87B + Meeus
840+ term series
→
03
Verified Against NASA
JPL Horizons System
Real-time comparison
Layer by Layer
Each celestial body uses the most accurate published algorithm for its orbital range.
⚙️
The Ephemeris Engine
Runs on DigitalOcean serverless (Node.js 18, global edge). Computes positions using published astronomical series — no black box. Returns geocentric tropical ecliptic longitude for 18 celestial bodies.
18 bodies · global edge
☀️
VSOP87B — Sun through Neptune
Bretagnon & Francou 1988, used by professional observatories. 840 terms for Neptune alone. Covers the range 1850–2150 with full precision.
< 0.001° (3.6 arcsec)
🌙
Meeus Chapter 47 — The Moon
Full 60-term series from "Astronomical Algorithms" (Jean Meeus, 1998). The standard reference in computational astronomy, used by planetarium software worldwide.
< 0.005° (18 arcsec)
🪐
Meeus Ch.37 + IAU76 — Pluto
43-term trigonometric series with IAU 1976 precession applied for ecliptic-of-date frame correction. Optimised for modern astrological and astronomical work.
< 0.003°
🪄
Hamburg School TNPs
Uranian / transneptunian points use conventional mean-motion orbits defined by Hamburg School tradition (Witte, Lefeldt). Used consistently across all Hamburg-method software worldwide.
~±1–2° Hamburg convention
✅
Independent Verification
Every result is checkable against NASA JPL Horizons in real time. Same ephemeris data used by NASA mission planners. Differences are typically smaller than the apparent diameter of a star.
JPL DE441 verified
Why NASA JPL Horizons?
NASA’s Jet Propulsion Laboratory Horizons System (JPL DE441) is the gold standard for planetary ephemeris data. It powers navigation for the Voyager probes, Mars rovers, and James Webb Space Telescope pointing. When we say our calculations match JPL, we mean they match the most precise solar system model ever built.
— NASA Jet Propulsion Laboratory · Horizons System (DE441) · In use for space missions since 1992
Accuracy Table
| Body |
Algorithm |
Accuracy |
Verified |
| Sun |
VSOP87B full series |
< 0.001° |
✓ JPL |
| Moon |
Meeus Ch.47 (60 terms) |
< 0.005° |
✓ JPL |
| Mercury–Saturn |
VSOP87B full series |
< 0.001° |
✓ JPL |
| Uranus |
VSOP87B full series |
< 0.001° |
✓ JPL |
| Neptune |
VSOP87B (840 terms) |
< 0.001° |
✓ JPL |
| Pluto |
Meeus Ch.37 + IAU76 |
< 0.003° |
✓ JPL |
| TNPs (8 bodies) |
Hamburg mean motion |
~±1–2° |
Hamburg convention |