Dusk is a pocket planetarium that draws the real night sky in WebGL. For any moment and place it renders the stars, constellations, Milky Way, deep-sky objects and planets exactly where they sit in the sky above you — wrapped in a warm dusk glow that fades from the horizon up to the zenith.
How it works. Everything you see is placed by genuine astronomy rather than a static picture. The whole celestial sphere is rotated for your latitude, longitude and the current clock using sidereal time, so the sky turns through the night just as the real one does. Thousands of stars are coloured from true blue–white to orange–red using each star's colour index and sized by brightness, and they twinkle gently. The seven naked-eye planets are computed live from Keplerian orbital elements, and the Sun and Moon from their own series, so their positions — and the glow the Sun casts along the horizon — match reality. Constellation figures, the softly-painted band of the Milky Way, and a catalogue of galaxies, nebulae and star clusters complete the scene, all fading away as they sink below a horizon ring marked N, E, S and W.
How you interact:
- Look around — drag to pan across the sky, and pinch or scroll to zoom the field of view in and out.
- Identify anything — tap a star, planet or deep-sky object and an engraved plate names it, with its designation, constellation and magnitude.
- Point at the sky — switch on motion mode to steer the view by physically aiming your device at the real sky; drag sideways to line up the compass heading.
- Tour the highlights — the focus button glides you from one notable sight to the next among everything currently above your horizon: the Moon, the planets, famous nebulae and the brightest named stars.
- Choose your layers — toggle stars, constellation lines, the Milky Way and deep-sky objects on or off.
- Set your place — tap the location chip to chart the sky for where you actually are, or pin coordinates in the URL; your layers and location are remembered for next time.
Dusk bundles its star catalogues so it runs completely offline, charting the live sky for your location and clock.