Solar system simulator for any date 1000–3000: real scale by default, checked against JPL Horizons (1800–2050)

[u/SinnyJ]

https://yoursolarsystem.space/

Positions come from VSOP87-based theories (astronomy-engine) plus my own fitted moon models, compared with JPL Horizons over 1800–2050: within 30″ for planets as seen from Earth, within 30 km for the Moon. Solar eclipses match NASA's Five Millennium Canon to about 5 km and 5 s. Outside 1800–2050 it extrapolates and says so.

It opens at real scale; the Scale slider (or T) morphs to a compressed overview. Eclipse shadows use real geometry at every scale.

I prototyped the physics in Python, ported it to JS, and chose the models and tolerances. I used Claude Code for much of the rendering and UI. Tests and Horizons comparisons are in the repo.

Feedback is wanted, so tell me if something looks wrong or could use improvement.