The map held 8750 stars within 50 pc and rendered 371 systems. Both were
lower than they needed to be, for different reasons.
The star catalogue was capped by its own encoding as much as by the
cutoff: one JSON object per star, eight key names repeated each time, 157
bytes a star. At the range HYG actually reaches that is 17 MB to download
and parse before the first frame. So the numbers move into two binary
column stores — positions in stars.bin, which the GPU is handed verbatim,
and id/magnitude/colour/spectral index in stars-meta.bin — and the JSON
keeps only the strings, with 2600 distinct spectral classifications
collapsed to a dictionary. The layout is defined once, in star-catalog.ts,
and the ETL and the app both use it, so the writer and the reader cannot
drift.
The cutoff then goes to 250 pc: 68388 stars, 7.8x as many for 1.7x the
bytes. That is where HYG's measurements stop rather than a round number —
98.6% of its rows are Hipparcos, whose parallaxes are good to about a
milliarcsecond, so beyond 250 pc it would be plotting noise.
Drawing all of them is a separate question from knowing them, and it is
answered separately. The field draws a budget: every star inside 25 pc,
because the nearest are faint red dwarfs and Proxima Centauri is magnitude
11, then the brightest of everything beyond. Search, navigation and the
planet cross-reference still see the whole catalogue. A real GPU would
draw all 68388 without noticing; the budget is for the machines that would
not, and it is one constant.
Systems were limited by something else entirely. The archive data already
shipped named 4735 host stars and only 388 resolved, because the rest lay
outside a 50 pc catalogue — and the cross-reference kept only its own
result, so redoing it meant re-downloading an archive that is not
reachable from here. Host coordinates are now stored with each planet, and
the match is re-resolved at build time against whatever catalogue the run
produced. Even name matching alone, which needs no coordinates and so
works on the records already shipped, rescues 335 planets across 238
systems: 371 renderable systems become 609.
Two selection rules were tuned for a 50 pc bubble and no longer fit.
Tethers followed the Sun's nearest neighbours, which are a speck at this
range, and now follow the brightest; labels were ranked by proximity,
which named whatever sat nearest the middle of the screen, and are now
ranked by brightness — so the view names Canopus, Achernar and Spica
rather than a clump of catalogue designations.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WaySiNst4HhDXBHnMy8p5G
Two ETL bugs, both fixed at the source and then re-run against HYG. Star ids,
ordering and positions are all unchanged, so stars.bin is byte-identical and
every exoplanet cross-reference still resolves.
Names. HYG's `gl` column already carries its own catalogue prefix ("Gl 581",
"GJ 3512"), unlike the bare numbers in `hd` and `hip`, so prefixing it again
produced 2331 of 8750 stars named "Gl GJ 1076". That corrupted three surfaces at
once: search, the on-screen labels, and exoplanet host-star name matching, which
compares normalised names and could never match "glgj1076" to "gj1076".
Colours. `Number(row['ci']) || 0` cannot tell a blank cell from a real zero, and
0 is a real B-V colour index meaning a hot blue-white A-type star. All 875
affected stars turned out to be blanks — the catalogue contains no genuine zero
inside the distance cutoff — so several hundred red dwarfs were rendering
blue-white. colorIndex is now `number | null` rather than defaulted, because any
numeric default is indistinguishable from a measurement.
Consumers resolve the gap from the spectral type instead. That needs real
parsing: HYG's `spect` column runs to 134 distinct spellings among the affected
stars alone, including a bare lowercase "m" for 354 of them, plus "k-m" ranges,
"dM4" luminosity prefixes and "K:" uncertainty flags. 622 of the 875 recover a
class this way — 497 of them M-class — and the remaining 253, which carry no
classification at all, fall back to neutral white.
The parse is anchored at the start of the string rather than scanning it. A scan
is the obvious implementation and is quietly wrong: the ETL writes the literal
"Unknown" for unclassified stars, that contains a K, and every one of those 253
would have been classified as an orange K-type. A test covers it.
Also lifts parseOptionalNumber out of fetchExoplanets into lib/csv, where both
fetchers now use it, and gives magnitude a faint default instead of 0 — no
current star is affected, but 0 would mean "as bright as Vega" and render an
unphotometered star as one of the largest points on the map.
Tests: 145 passing, up from 116, including the first coverage of
StarFieldRenderer. Build, both typechecks and the Playwright suite are green.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WaySiNst4HhDXBHnMy8p5G
Add star-map Angular app, ETL pipeline, and caveman plugin
Angular 3D star map (galaxy/system/body views, Three.js rendering,
navigation store) plus the NASA ETL tooling that builds the star,
exoplanet and solar-system datasets, Playwright e2e suite, and the
cs:caveman Claude Code plugin (command, agent, skill).
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
@
Claude
Senrokai