Credit the sources the solar system's orbits now come from, in the README and a search comment

Since 48319c3 and 1d42be2 no position comes from Horizons: the planets move on Standish's mean
elements (Table 2a/2b), the moons on JPL SSD's satellite table, Ceres, Eris, Haumea and Makemake
on the Small-Body Database's osculating elements, and every body turns by the IAU's rotational
elements from NAIF's pck00011. bodies.json's orbitSource values say so (9 Standish, 25 satellite
table, 4 SBDB, none Horizons). Horizons gives sizes, spins and the positions the ETL checks
against. The README still credited "Solar-system ephemerides: NASA/JPL Horizons", said the Sun's
bodies came "from JPL Horizons", listed fetchSolarSystem's source as "JPL Horizons / SSD", and had
Horizons reporting every element against the ecliptic, where the moons' are against a Laplace
plane or their planet's equator. The branch had edited the credits paragraph and left that line.
search-ranking.ts called the solar-system bodies "eighteen famous objects"; there are 38.

Documentation only; no behaviour changes.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
This commit is contained in:
2026-09-29 19:57:50 +02:00
co-authored by Claude Opus 5.5
parent a281f22f34
commit 98c4eb901f
2 changed files with 9 additions and 6 deletions
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@@ -53,9 +53,11 @@ in it is measured and what is not.
![The solar system: orbit ellipses over a dashed reference grid marking 5 AU rings out to 35 AU](docs/screenshots/system-view.jpg)
**System view** — selecting a star flies the camera continuously into its system rather than
cutting to a new scene. The Sun gets the real solar-system bodies from JPL Horizons; other
cutting to a new scene. The Sun gets the real solar-system bodies, moving on JPL's mean orbital
elements — Standish's for the planets, JPL SSD's satellite table for the moons, the Small-Body
Database for Ceres, Eris, Haumea and Makemake — and turned by the IAU's rotational elements; other
stars get their confirmed exoplanets. Orbits are drawn as ellipses and bodies are propagated
along them by a Kepler solver against the current epoch. Under them, a dashed grid marks out
along them by a Kepler solver to the date on the map's clock. Under them, a dashed grid marks out
round distances in AU — 5 AU rings for the solar system, 0.01 AU rings for TRAPPIST-1 — with a
drop line from each body, so eccentricity and inclination read against a circular reference
instead of having to be inferred from a shape in space. The camera frames that grid rather than
@@ -109,7 +111,8 @@ its own readout, so a stale image is visible as one.
both backends. Their size is angular rather than world-space — real stars are unresolvable
point sources, so apparent size should follow brightness, not distance.
- **One reference frame, from three sources.** HYG gives star positions in equatorial J2000.
JPL Horizons reports orbital elements against the ecliptic, tilted 23.4° away. The Exoplanet
JPL gives the planets' orbital elements against the ecliptic, tilted 23.4° away, and the moons'
against the ecliptic (the Moon), a Laplace plane, or their planet's equator (Uranus's and Pluto's). The Exoplanet
Archive measures inclination from the *plane of the sky* — perpendicular to our line of sight
to each host star, which is why transiting planets cluster at 90°. Each set of elements is
rotated from its own reference plane into the scene's equatorial frame, so a direction means
@@ -202,7 +205,7 @@ re-runs are cheap and offline-friendly; set `ETL_FORCE_REFRESH=1` to bypass the
| Script | Source | Output |
| --- | --- | --- |
| `fetchStars.ts` | HYG database, plus any other positional catalogue wired in (see below) | `stars.bin`, `stars-meta.bin`, `stars-index.json` |
| `fetchSolarSystem.ts` | JPL Horizons / SSD | `bodies.json` |
| `fetchSolarSystem.ts` | JPL SSD mean elements (Standish's planets, the satellite table), the Small-Body Database, NAIF's PCK, JPL Horizons | `bodies.json` |
| `fetchExoplanets.ts` | NASA Exoplanet Archive (TAP) | `exoplanets.json` |
| `fetchDeepSky.ts` | OpenNGC | `deepsky.json` |
@@ -326,7 +329,7 @@ plugin's own files are kept so it can be listed from a marketplace of its own la
## Data credits
Star catalogue: [HYG database](https://github.com/astronexus/HYG-Database) (Hipparcos, Yale
Bright Star, Gliese) — 68 388 stars within 250 pc. Solar-system ephemerides: NASA/JPL Horizons. Exoplanets: NASA Exoplanet
Bright Star, Gliese) — 68 388 stars within 250 pc. Solar-system orbits: JPL approximate planetary mean elements (Standish), JPL SSD satellite mean elements and the JPL Small-Body Database; rotation: the IAU WGCCRE 2015 report via NAIF's pck00011; physical data, and the positions the orbits are checked against: NASA/JPL Horizons. Exoplanets: NASA Exoplanet
Archive. Deep-sky objects: [OpenNGC](https://github.com/mattiaverga/OpenNGC). Body and skybox
imagery: NASA/JPL/USGS public domain and Solar System Scope (CC BY 4.0) — per-file provenance
is recorded in `src/assets/textures/README.md`.
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@@ -21,7 +21,7 @@ const MATCH_SUBSTRING = 1;
const NO_MATCH = 0;
/**
* Order for results that match equally well. Solar-system bodies are eighteen famous objects
* Order for results that match equally well. Solar-system bodies are a few dozen named worlds
* and win ties outright; a star outranks an exoplanet because searching a name like "Proxima"
* is usually an attempt to reach the system rather than one particular planet in it.
*/