See how Earth's 1 AU orbit baseline turns a tiny parallax angle into stellar distance - d (pc) = 1/p (arcsec), with 1 pc about 3.26 ly (about 206,265 AU) and Proxima Centauri at about 0.7687 arcsec.
Blue and green sight lines run from opposite ends of Earth's orbit to the star. Star depth scales with 1/p so a larger parallax pulls the star closer on the teaching stage.
Angles are exaggerated for the camera - real stellar parallaxes sit below one arcsecond. This isolates the measurement triangle Solar System 3D Explorer does not teach.
Parallax Distance 3D Explorer
See how Earth's 1 AU orbit baseline turns a tiny parallax angle into stellar distance - d (pc) = 1/p (arcsec), with 1 pc about 3.26 ly (about 206,265 AU) and Proxima Centauri at about 0.7687 arcsec.
Drag to orbit the view, scroll or pinch to zoom, and try Proxima, 1 arcsec, and 0.5 arcsec presets. Formula and Earth baseline buttons fill the facts panel.
The facts panel lists d = 1/p, 1 pc about 3.26 ly = about 206,265 AU, and Proxima Centauri parallax about 0.7687 arcsec.
- Sun plus Earth at opposite orbit ends as the teaching baseline
- Sight lines to a distant star that move with parallax presets
- Proxima Centauri preset at about 0.7687 arcsec
- 1 arcsec = 1 parsec and 0.5 arcsec = 2 pc literacy buttons
- Distinct from Stellar Magnitude Scale Explorer and Milky Way Map 3D Explorer
- Runs fully in the browser with the vendored three.js engine - no account, no upload
Teachers use it to show why one arcsecond defines one parsec, students scrub Proxima versus 1 arcsec, and curious readers connect a tiny angle on the sky to a light-year distance without opening a catalog alone.
| Quantity | Value | Source |
|---|---|---|
| Parallax distance | d (pc) = 1 / p (arcsec) | Definition of the parsec |
| 1 parsec | about 3.26 ly | Standard conversion |
| 1 parsec in AU | about 206,265 AU | 1 / tan(1") geometry |
| Proxima Centauri parallax | about 0.7687 arcsec | Published Proxima p (Hipparcos/Gaia era summary) |
Everything renders on your device with WebGL. The 3D engine loads once (about 0.7 MB) and is cached; no scene data is sent to a server.
The scene is an educational visualization - sight-line angles are exaggerated so the triangle stays readable. It is not a Hipparcos reduction pipeline or a precise ephemeris.
For a step-by-step walkthrough, read the Parallax Distance 3D Explorer step-by-step guide. The Space 3D collection also includes a Stellar Magnitude Scale Explorer for brightness scales and a Milky Way Map 3D Explorer for galactic structure.
Frequently Asked Questions
What does Parallax Distance 3D Explorer show?
Earth at opposite ends of a 1 AU orbit, sight lines to a star, and how changing parallax in arcseconds moves the star with distance d = 1/p in parsecs.
What is the parallax distance formula?
d (pc) = 1 / p (arcsec). A star with parallax 1 arcsec sits at 1 parsec; 0.5 arcsec sits at 2 pc.
How far is one parsec?
About 3.26 light-years, or about 206,265 AU - the distance where Earth's orbit subtends one arcsecond.
What about Proxima Centauri?
Its published parallax is about 0.7687 arcsec, which implies about 1.30 pc (~4.24 ly) with d = 1/p.
How is this different from Stellar Magnitude Scale Explorer?
Stellar Magnitude Scale Explorer teaches apparent vs absolute brightness. Parallax Distance 3D Explorer isolates the Earth-baseline triangle that measures distance.
Are the on-screen angles true to scale?
No. Real stellar parallaxes are below one arcsecond, so the teaching stage exaggerates the triangle so the geometry stays readable.