How Skyhook is made

Every Skyhook tour is a genuine render of the Earth as it looked that day — not stock footage, not a repeating animation. Here's what goes into one.

A renderer built for one planet

Skyhook's tours are produced by our own rendering engine — a native application, purpose-built to draw the Earth from orbit — running daily on our hardware. The finished tour is delivered to the app as ordinary video, so on your desktop the cost is just hardware video decode: no 3D rendering happens on your machine.

• Physically-based light, end to end. The whole pipeline works in linear high-dynamic-range radiance — sunlight, sky, clouds, ocean, and city lights are computed in physical units and only converted to a displayable image at the final tone-mapping step, the way film and cinema renderers do it.
• A real atmosphere. Sky color, sunrise and sunset hues, and the blue haze of distance all come from precomputed atmospheric-scattering tables (the Bruneton/Hillaire model) built on standard Earth Rayleigh, aerosol, and ozone physics — not painted gradients.
• Volumetric clouds, marched every frame. Clouds are rendered by ray-marching a 3D density field: satellite measurements supply each cloud system's coverage, top, base, thickness, and type, and procedural detail noise fills in the fine billows. Cloud self-shadowing is computed per sample, so towering systems light the way real ones do — including a separate high cirrus veil above the main deck.
• Terrain with relief and shadow. The globe is a streamed tile pyramid: GPU-tessellated 30-meter elevation, real bathymetry-tinted oceans with wind-driven sun glint, and terrain self-shadowing so mountain ranges cast honest shadows at low sun.
• An honest night side. City lights use calibrated radiance measurements — physically about a hundred thousand times dimmer than the daylit surface, revealed by the camera's exposure just as they would be from a real orbital platform — under moonlight, a catalog-accurate starfield, and the Milky Way, all pinned to the true sky for the render's date and time.

Where the data comes from

Every pixel is built from open, commercially-usable agency data — NASA, NOAA, and ESA/Copernicus missions:

• Clouds (near-real-time): the NOAA/JPSS VIIRS cloud suite from three polar-orbiting satellites (Suomi-NPP, NOAA-20, NOAA-21) — ~750 m resolution retrievals of cloud cover, top height, and optical thickness, reaching us about an hour after observation. Cloud base is modeled with NOAA's published cloud-base algorithm.
• Surface color: ESA Copernicus Sentinel-2 quarterly mosaics (~10 m surface reflectance).
• Terrain & ocean floor: Copernicus DEM GLO-30 (~30 m elevation) and NOAA ETOPO 2022 global relief and bathymetry.
• Surface materials: ESA WorldCover land-cover (10 m), driving roughness and the water/land distinction.
• City lights: NASA Black Marble (VIIRS Day/Night Band) — calibrated nighttime radiance, not an artist's glow map.
• Ocean winds: an ERA5 reanalysis climatology, shaping how the sun glints off the sea surface.
• Stars & Moon: the HYG star catalog (Hipparcos/Yale) for bright stars, NASA's "Deep Star Maps 2020" (Gaia/Tycho-2) for the Milky Way, and NASA's LRO-derived Moon Kit for the lunar disc.

From render to your desktop

Each day the newest satellite cloud data is baked into the global scene, a cinematic orbit is rendered in 4K, encoded as standard H.264 video with chapter markers, and published to our CDN. The app quietly downloads the newest tour in the background and keeps playing the latest one it has — even offline.

Data attributions

Skyhook is built on open Earth data, with thanks to the agencies and teams who publish it freely:

• Contains Copernicus Sentinel data (surface color; Copernicus DEM © ESA/Airbus).
• © ESA WorldCover project 2021 / Contains modified Copernicus Sentinel data 2021.
• Contains modified Copernicus Climate Change Service information (ERA5). Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.
• NOAA ETOPO 2022 and the NOAA/JPSS VIIRS cloud suite, courtesy of NOAA (public domain).
• NASA Black Marble, NASA CGI Moon Kit, and "Deep Star Maps 2020" courtesy of NASA and NASA's Scientific Visualization Studio (public domain).
• Bright-star data derived from the HYG database (astronexus.com), built on ESA Hipparcos and the Yale Bright Star Catalogue.