[craig-o-curtis]

Hovering a star now traces its constellation across the sky, every star the sky draws has a label, and tooltips, cards and buttons fade in instead of popping.

Changes

• Constellation lines: hover or tap a star and its constellation draws itself outward from that star, line by line, then fades a moment after you leave. Moving between stars of the same constellation keeps the drawing.
  • Lines stop short of each star and break where they would pass below the horizon or behind the skyline.
  • They sit under the cards, so the glass blurs them like the stars.
  • The worker projects them; the page only draws SVG lines. Nothing runs until a hover.
  • Figures are d3-celestial's (Olaf Frohn, BSD-3-Clause), matched to our star catalogue: 739 lines, 2.3 KB gzipped. Credited in the popover.
• Labels for every star: previously only the 324 IAU-named stars had one.
  • Named stars are unchanged: "Sarin · Hercules".
  • 1,801 more show their Greek-letter or Flamsteed designation: "ζ Herculis", "95 Herculis".
  • The remaining 762, mostly faint southern stars, show their catalogue number: "HR 104".
  • The names file grows from 3 KB to 19 KB gzipped and still loads after the stars.
• Tooltip fade: labels rise into place out of a soft blur on the theme's enter timing and fade out. Reduced motion keeps only the fade.
• Cards and buttons: on hover a card's border brightens and a soft glow fades in, and fades back out quicker. The Docs and GitHub buttons do the same; their glow is a separate layer, so it never fights the focus ring.

Verification

• Checks: pnpm lint, pnpm check and pnpm build pass on every commit. stars.bin is unchanged byte for byte.
• Star positions vs astronomy-engine: 10 bright stars at both sites agree within 0.3′.
  • Andromeda sits left of centre at Ísafjörður and right of centre at Helsinki, which is correct. Ísafjörður faces NNE with Andromeda in the NNW; Helsinki faces NNW, three hours later in local time, with Andromeda in the N–NNE.
• Labels: in headless Chromium, 26 of 27 stars found on screen over Helsinki got a label. The miss was likely a city light on the horizon.
• Constellation tracing: checked visually for Perseus and Auriga.
• Fade timing: not judged in headless runs, because the software renderer is too slow for that. Worth a look on a real screen.

[baldurpan]

Nice work. I checked the build scripts against the Bright Star Catalogue and the pinned d3-celestial file:

• The Greek-letter map and the superscript digits cover every Bayer name in the catalogue.
• Every figure vertex lands within 0.6′ of its star.
• Every constellation in star-names.json has a figure.

The header fix in 5e5f023 looks right too.

I found two things, both inline: 20 figure stars that draw nothing when you hover them, and lines that stay where they were drawn when the view changes. I'll approve once both are settled, whether you fix them or answer them.

[baldurpan]

Approving at 11550c6. Both findings are fixed: figure stars that have no constellation now draw their figure, and the lines and the label follow the sky after a resize and as it turns. I read the whole diff of 11550c6 and found nothing new. CI passes.