Earthlight

Earth, the Moon and the sky from orbit, rendered live in the browser. Fly anywhere, pick any date and shoot it through a simulated camera.

Open Earthlight, or read how it was made.

Ride the International Space Station on its real orbit, switch to a polar or a high orbit, or leave orbit and fly anywhere from 150 to 50,000 km. Set any date from 1900 to 2100 and the Sun, the Moon's phase, the planets and 15,598 real stars move into place. Zoom a 0.5–50× lens onto city lights, mountain ridges or the craters of the Moon. Every frame is drawn live by one WebGL renderer, with no Three.js and no video, and exposed by one simulated camera.

These are unedited frames. The address bar follows the view, with the time, position, lens and exposure, so click any picture to open that exact view.

What you can do

• Fly anywhere. Follow the ISS, a polar orbit at 800 km or a high orbit at 20,000 km, or fly freely between 150 and 50,000 km. Grab the ground and drag it, flick to coast, circle a pinned point, double-click to fly in, and let the horizon gauge turn you toward the Sun, the Moon or the Earth.
• Pick any moment. Any date from 1900 to 2100, any time of day, time running from paused to 1,000×. The day–night line, the Moon's phase, the planets and the stars all follow it.
• Zoom from 15 to 1,500 mm. At 50× the Moon resolves into NASA's colour and relief maps with libration, the Sun becomes a limb-darkened disk, and on Earth close-up relief and city lights on their native 1 km grid stream in.
• Shoot it like a camera. Automatic or manual exposure with compensation from −3 to +4 EV, a coated ISS lens or a flare-prone one, and dials for flares, grain, colour separation and the Milky Way. Night mode (N) draws the night at its physical brightness through a camera set like ISS night video.
• Change the sky. Clouds come in Calibrated, Balanced or Original density or not at all, and the aurora can be on, off or left to the device.
• Share the exact frame. Copy the address bar and anyone opens the same view at the same moment, paused or running.
• Use any input. Mouse, trackpad, touchscreen and keyboard each have their own gestures, Help shows only the ones your devices have, and phones get a touch layout with haptic ticks.
• Embed it. The same renderer runs as a quiet page background, without controls. It is behind the homepage of maxvyshniakov.com.

What is in the frame

• A real orbit. A saved CelesTrak element set for the ISS (NORAD 25544), propagated with SGP4: about 93 minutes a lap at roughly 420 km, sixteen sunrises a day. Earth turns by apparent sidereal time, and Astronomy Engine places the Sun, Moon and planets from Mercury to Saturn with precession and nutation.
• The sky. 15,598 stars from the HYG catalog down to magnitude 7, with proper motion, colour from B−V and brightness from magnitude. Positions match NASA's Deep Star Maps to a median of 1.35 arcminutes. The Milky Way is NASA's map, streamed in tiles up to 16K. The Moon carries NASA's lunar colour and elevation maps and is lit by the real Sun.
• Atmosphere and airglow. Rayleigh scattering through an exponential atmosphere, with Earth's shadow and wavelength-dependent extinction: the blue limb by day and the orange band at twilight. Sunlight grazing the limb is refracted and dimmed, and a thin aerosol puts a glow around the Sun. Airglow shells at 90 and 98 km add the faint amber and green layer above the night horizon.
• Aurora. Curtains follow an oval built on the WMM2025 magnetic dipole, wider toward magnetic midnight. The green lower edge varies between about 99 and 137 km and the red layer peaks at 245–330 km. Thin rays, the curtain body and the diffuse glow between curtains are rendered as a volume.
• Clouds. NASA's July 2001 cloud-cover composite, lifted into a volume between 0.6 and 12 km whose tops and gaps come from the data, not from noise. The default opacity is fitted to NASA's own composite to within 0.011 RMS over dark ocean. Clouds cast shadows, catch the low sun, dim the cities beneath them and flicker with lightning.
• Surface, sea and cities. NASA Blue Marble at 500 m per pixel (86,400 × 43,200) and Black Marble night lights, streamed tile by tile into bounded GPU atlases; the night side loads only tiles that contain light. The Sun and Moon glint on the ocean. Relief comes from ETOPO 2022 and, close up, Copernicus GLO-90.
• One camera for every light. No object has its own brightness. A light meter reads the frame on the GPU and sets aperture and ISO at a fixed 1/48 s shutter. The lens is modelled on the 28–300 mm the crews use, with nine rounded blades: its eighteen diffraction rays, coated internal reflections, dirt veil and defocus follow from each source's real light. The sensor turns photons into electrons with shot and read noise, swipes blur like a film camera's, and the image is encoded once, in Display P3 where the screen supports it.

Controls

Tapes around the frame set the time scale, date and time of day along the top, exposure and the lens on the left, and altitude and the orbit on the right. The horizon gauge at the bottom levels the camera, and its Sun, Moon and Earth markers turn you to face them. The gear opens Settings.

	Keyboard	Mouse and trackpad	Touch
Fly	W A S D	Drag, or scroll on a trackpad; flick to coast	Drag; flick to coast
Look around	Arrow keys; \ levels the horizon	Shift-drag or middle-drag, two-finger press and drag, or Shift-scroll	Drag with two fingers
Circle a point		Right-drag, or drag, scroll or wheel with Control
Roll	Q E; H levels or flips	Option-drag around the centre, Option-wheel, or rotate two fingers in Safari	Twist two fingers
Closer, farther	F R	Shift-wheel or Option-scroll; double-click to fly in, Shift-double-click to back off	Double-tap to fly in, two-finger tap to back off
Zoom the lens	+ −; 0 for 1×	Wheel or pinch	Pinch
Orbit	1 free, 2 ISS, 3 polar, 4 high	Buttons on the right	Buttons on the right
Time	Space pauses and plays	The time tape	The time tape

Hold Shift to go faster. N switches night mode, M and T pick a mouse or a trackpad, I shows the credits and ? opens Help.

Performance

The scene is tuned on a weak GPU, an Intel UHD 630, and a Pixel 9 Pro XL rather than on a fast laptop, so every effect pays for its milliseconds.

• First light. The first frame is a defocused poster of a few kilobytes, chosen by where the Sun is. Low-resolution overviews follow, then detail for the visible region, and the lens pulls focus as it arrives. On slow 4G first light is complete in 1.08 s.
• Frame rate. Render resolution adapts to measured frame delivery, and the settled scale is remembered per device. Brief stalls don't count as overload, so desktop swipes run at 51–54 frames per second.
• Robustness. A failed tile falls back to the overview, and a device that can't render gets the poster instead of a blank screen. The renderer recovers from WebGL context loss, pauses off screen and frees GPU memory when detached.

How it is built

• <earthlight-explorer> is a framework-free custom element, about 15,500 lines of TypeScript and GLSL in src/scripts/. Astro only hosts the demo page.
• WebGL2 where it exists, WebGL1 as the fallback, compiled from one shader dialect. Terrain decodes in workers.
• Scene data ships as a versioned, checksummed release of about 12,000 files, served with an immutable cache. The pipelines in scripts/ rebuild every texture and catalog from the original sources.
• 357 unit tests, browser checks that drive the rendered scene, and 71 dated lab notes with the measurements behind each decision.

The docs explain the model, the data and the measurements in detail, including what is approximate.

Run it locally

Requires Bun 1.3.14.

bun install --frozen-lockfile
bun run assets      # download and verify the pinned scene data
bun run dev         # http://localhost:4321/

bun run verify runs the unit tests, type checks and a production build. Unit tests need the downloaded scene data. bun run verify:scene <url> <output-dir> drives the rendered scene in an isolated agent-browser session.

Embed the background

The earthlight/background Astro component runs the same renderer as a passive background: it follows the ISS, scrolls with the page and leaves page input alone. It keeps a static poster when reduced motion is requested or the GPU is emulated in software.

---
import Background from 'earthlight/background';
import assets from 'earthlight/assets-manifest';
---
<Background assetBaseURL={`https://media.maxvyshniakov.com/earthlight/${assets.version}/`} />
<a href="https://earthlight.maxvyshniakov.com/">Explore Earthlight</a>

The package also exports the explorer as an element and as an Astro component, the terrain proxy and an Astro integration for local assets. See integration and releases for package updates, asset publication and deployment.

Honest limits

The ISS is a replay, not live tracking: its orbit comes from one saved element set. The clouds are a single global composite, not the weather on the chosen date. The aurora is procedural on a real magnetic model, and the lightning is illustrative. The camera is plausible, not calibrated, and the default night is many times brighter than a real camera would see it; that is a choice, and night mode shows the physical one. A day of measured clouds, a 62.5 m daytime surface and measured night radiance exist as experiments behind URL flags but are not in the data release. Do not navigate with it.

How it was made

Earthlight started as a homepage background and a wallpaper made from an ISS photograph, and grew over two weeks with AI agents into what you see here. The wallpaper stayed the bar the whole time. The case study tells the story: the first-evening rollback, the camera rebuilt around one light meter, eight rounds of notes on the aurora, and a weak GPU as the benchmark.

Credits

Imagery: NASA Earth Observatory (Blue Marble, Black Marble) and NASA/GSFC Scientific Visualization Studio (Deep Star Maps, with Gaia DR2 from ESA/Gaia/DPAC, and the CGI Moon Kit from LRO LROC and LOLA). Stars: HYG v4.1 by David Nash (CC BY-SA 4.0). Terrain: NOAA ETOPO 2022 and Copernicus DEM. Magnetic field: WMM2025 (NOAA NCEI and BGS). Orbital elements: CelesTrak. Libraries: satellite.js, Astronomy Engine, geotiff.js. NASA, ESA and the other data providers do not endorse this project. Full terms and the changes made to each source are in NOTICE and the data provenance notes.

License

The code is MIT. The scene data keeps its sources' terms, listed in NOTICE; for example, the star catalog is CC BY-SA 4.0.

If you use Earthlight in something you make, I would appreciate a visible credit near the scene, such as "Earthlight by Max Vyshniakov" linking to earthlight.maxvyshniakov.com. The license does not require it, but it helps people find the project.

---

Made by Max Vyshniakov.