3D Orrery · Real NASA Data

A simple, real-time 3D model of the solar system using actual NASA/JPL orbital elements. Built with Three.js. No build step, no dependencies to install.

How to run

1. Save orrery.html somewhere on your computer.
2. Double-click it — it opens in your default browser.

Requires a modern browser (Chrome 89+, Firefox 108+, Safari 16.4+). If the page is blank, the CDN is being blocked over file://. Run a tiny local server in the same folder:

python3 -m http.server 8000
# then open  http://localhost:8000/orrery.html

Controls

• Drag — rotate the view
• Scroll — zoom
• Right-drag — pan
• Click any planet — see its current distance, true anomaly, etc.
• Time speed slider — from 0.01 d/s (reverse) to 10 000 d/s
• Speed buttons — pause, 1 day/s, 1 week/s, 1 month/s, 1 year/s
• Date picker — jump to any date (year 0 … 9999)
• Now — back to the present
• Orbits / Labels / Real scale — display toggles

Data source

Orbital elements come from NASA JPL's Keplerian Elements for Approximate Positions of the Major Planets — the same dataset used for mission planning. Public domain:

https://ssd.jpl.nasa.gov/planets/approx_pos.html

Each planet has six elements and their rates of change per Julian century: a (semi-major axis, AU), e (eccentricity), I (inclination, deg), L (mean longitude, deg), ϖ (longitude of perihelion, deg), Ω (longitude of ascending node, deg).

For any Julian Date, the code extrapolates these elements with their rates, solves Kepler's equation M = E − e·sin(E) by Newton–Raphson, and rotates the result into heliocentric J2000 ecliptic coordinates.

Accuracy

Good to a few arc-minutes for dates within a few centuries of J2000.0 — more than enough to show exactly where the planets are right now. NASA's own navigation uses more elaborate models (JPL DE440 etc.) with planetary perturbations and relativistic corrections, but those are overkill for a visual orrery.

Performance

• 8 planets + Sun
• 7 000 procedural background stars
• ~2 000 line segments for orbits
• No textures loaded
• Runs at 60 fps on anything from the last decade
• Total file size: ~30 KB

License

Code: MIT. Orbital data: public domain (NASA/JPL).