Files
German KhokhlovandClaude Opus 5.5 8c33c6f349 docs(sky): shorten the sky comments and README, fix three stale ones
The far-plane comment said z = w (the code puts z just under w), the Milky
Way constant is a brightness, not an opacity, and the CDS acknowledgement
lives in the Data attribution popover, not DATA_SOURCES.md.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
2026-10-20 13:56:44 +04:00

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Sky background

Catalogue stars over a soft Milky Way, drawn by src/sky/starrySky.js in place of Cesium's blocky Tycho-2 sky box.

File Content Size
bright_stars.json 9,096 stars: J2000 RA/Dec, V magnitude, B−V 235 KB
milkyway_{px,nx,py,ny,pz,nz}.webp Milky Way glow, six 1024² cube faces, no stars 62 KB

Stars — Yale Bright Star Catalogue

Source: 5th Revised Edition (Hoffleit & Warren 1991), CDS catalogue V/50, file https://cdsarc.cds.unistra.fr/ftp/V/50/catalog.gz (sha256 3dc44b1e90be8fbe5bcc7656032560f51275f985c7e3f783c9028e1838ec7bed, fetched 2026-10-19).

License: public domain. CDS asks for an acknowledgement; the "Data attribution" popover carries it.

Build: node scripts/build-bright-stars.mjs [catalog.gz]. Drops the 14 records without a J2000 position; rounds RA/Dec to 0.001° and magnitudes to 0.01.

Milky Way — ESO/S. Brunier

Source: ESO image eso0932a, https://cdn.eso.org/images/original/eso0932a.tif (6000×3000 sRGB TIFF, sha256 10f209ab83e1fd89e7fa1ed70277ffc6ed19c43549f04ec637c6806d98aff035, fetched 2026-10-19).

License: CC BY 4.0. Credit: ESO/S. Brunier.

Changes made (CC BY 4.0 asks for them): resampled to 4096×2048; stars removed; two images of Jupiter painted over; blurred (0.4°, 2° in the faint glow); reprojected to ICRF cube faces; black level at the median sky; saved as WebP. Build: node scripts/build-milky-way.mjs <eso0932a.tif>.

The panorama's stars sit up to ~2° off; that is invisible in the blurred glow, and every sharp star comes from the catalogue.

NASA SVS "Deep Star Maps 2020" was not used: it derives from Gaia DR2, which ESA licenses CC BY-NC 3.0 IGO.

Frame

Both layers are in ICRF/J2000. The cube faces use the WebGL face layout, +X to the March equinox and +Z to the north celestial pole, uploaded without flipY.