asc_sky

Dusk-to-night skydome shader for the ascension finale. Rendered on the inside of a large inverted sphere at the part center. The sun position tracks the scene's directional light, so the part's animated sunset sinks the HDR sun disk and horizon ember for free; the night property (0..1) deepens the zenith to near-black, tightens the ember band, fades the cirrus, and brings out two twinkling star layers plus a faint milky band. A per-direction dither keeps the smooth gradients from banding.