What can be shown in true 3D
A three-dimensional universe is only as honest as its coordinates. This page states exactly which objects have measured positions and distances — and which do not — so every scene can be read for what it is.
The measured data
| Measure | Count | What the scenes do with it |
|---|---|---|
| Stars with a measured distance | 2,887 of 2,944 | Placed in true 3D in the stellar-neighbourhood scene (parallax distance). |
| Stars without a measured distance | 57 | Excluded from every distance-true scene — never placed at a guessed position. |
| Stars with a measured direction | 2,944 | Right ascension and declination — enough for the celestial-sphere (direction-only) scenes. |
| Deep-sky objects with a direction | 619 of 619 | Direction and angular size only. |
| Deep-sky objects with a distance | 0 | The catalogue carries no line-of-sight distance for deep-sky objects, so none is placed in true 3D. |
| Planets with a real orbit | 8 | Real semi-major axes drive the to-scale Solar System scene. |
| Galactic structures (Milky Way) | 11 | Descriptive only — no numeric galactic geometry, so no galaxy-scale scene is fabricated. |
| Cosmic structures (Local Group +) | 6 | Descriptive scale labels only — no numeric inter-galactic distances. |
How each scene is drawn
- Constellations on the Celestial SphereInteractive
Direction only — the celestial sphere
Measured right ascension and declination placed on the unit celestial sphere (direction only — no distance is asserted by the position). Each star's measured distance is shown in the accompanying table.
- The Local GroupDescriptive
Descriptive — no numeric geometry available
The catalogued galaxies and cosmic structures carry descriptive scale labels only — no numeric distance or coordinate — so no distance-true extragalactic scene is fabricated.
- The Local Stellar Neighbourhood in 3DInteractive
Distance-true — real measured 3D positions
Measured right ascension and declination with a measured parallax distance (light-years) for each star, converted to real Cartesian positions. Stars without a measured distance are excluded — never placed.
- The Milky WayDescriptive
Descriptive — no numeric geometry available
The catalogued galactic structures carry descriptive text only — no numeric coordinate or distance — so no galaxy-scale scene is fabricated. The only measured 3D geometry available at this scale is the local stellar neighbourhood, which is linked.
- The Solar System in 3DInteractive
To scale — real relative distances
Real semi-major axes (astronomical units) from the solar-system catalogue; orbit sizes are to scale. Each planet is marked on its orbit at an illustrative angle — the along-orbit phase is schematic, not a computed ephemeris.
The rule
No position, distance, or coordinate is ever fabricated. An object with no measured distance is never placed in a distance-true scene; a structure with only a descriptive scale label is never given invented coordinates. See source quality.