EARTH — ORBITAL VIEW

Regional textures for the close view:
- earth-orbit-day.jpg: 3072 × 2304, cropped from the NASA 21600 × 10800 map.
- earth-orbit-clouds.jpg: 2560 × 1920, cropped from the NASA 8192 × 4096 TIFF.
- earth-orbit-night.jpg: 2048 × 1536, cropped from the NASA 13500 × 6750 map.
Shared extent: 80° West to 40° East, 10° South to 80° North.
Top = 80° North; left = 80° West. Equirectangular projection.
All three crops were downsampled from their originals without upscaling.
The former global maps are no longer loaded or included in this view.

Surface: NASA Earth Observatory / Reto Stöckli, NASA Goddard Space Flight Center.
Blue Marble: Next Generation, July 2004.
https://science.nasa.gov/earth/earth-observatory/blue-marble-next-generation/base-map/

Clouds: NASA Goddard Space Flight Center / Reto Stöckli; enhancements by Robert Simmon.
Blue Marble: Clouds, historical 2001/2002 composite.
https://eoimages.gsfc.nasa.gov/images/imagerecords/57000/57747/cloud_combined_8192.tif
NASA historical composite context: https://svs.gsfc.nasa.gov/3402/

Night lights: NASA Earth Observatory / Joshua Stevens, based on Suomi NPP VIIRS
data from Miguel Román, NASA GSFC. Black Marble 2016, greyscale version.
https://science.nasa.gov/earth/earth-observatory/earth-at-night/maps/
https://science.nasa.gov/earth/earth-observatory/night-light-maps-open-up-new-applications-90008/

NASA usage guidelines:
https://www.nasa.gov/nasa-brand-center/images-and-media/

Textures are hosted locally, resized and compressed for this experience.
Exact sources, transformations, extents, UVs and SHA-256 hashes: earth-sources.json.
Surface, cloud and night-light maps are historical composites from different dates.
The cloud mask does not measure cloud altitude; the night map is a visualisation,
not a radiometric measurement intended for scientific use in this experience.
Lighting, light colours, atmospheric glow and orbital composition are artistic
interpretations. These are neither live images nor a calculated real orbit.
No NASA affiliation or endorsement is implied.

Atmosphere: original transmission lookup table generated by scripts/prepare-earth-atmosphere.py.
Simplified single-scattering Rayleigh/Mie model with ozone, eight samples per ray.
The 256 × 128 table uses horizon-distance coordinates and stores sqrt(transmission)
in RGB8; its offline integration uses 512 samples. See earth-transmittance-sources.json.
Technical references: https://ebruneton.github.io/precomputed_atmospheric_scattering/
and https://github.com/cosmoscout/cosmoscout-vr/blob/main/plugins/csp-atmospheres/README.md
No code from these projects is incorporated.