Solar Observatory

v0.6.1 · pre-release

A real-time 3D map of the solar system. Planets, moons, dwarf planets, asteroids, comets, spacecraft, and Lagrange points are placed using live orbital data from NASA JPL Horizons, the same ephemeris system used for real mission planning. This is an early build — see the accuracy notes below.

How it works

For planets, moons and small bodies, the app fetches each body's osculating orbital elements from Horizons and propagates them with Kepler's equation in your browser — which is why you can scrub time freely. Spacecraft and Lagrange points aren't simple ellipses, so those use sampled trajectory tables from Horizons instead. Each body's rotation (day/night, the terminator line) is set from the IAU pole and prime-meridian model, so the lit face is correct for the current time.

Getting around

Camera

Drag to orbit, scroll to zoom, right-drag to pan. Click any body — or its orbit line — to focus and track it. Use the search box or the grouped list on the left to find and select anything.

Time controls (bottom)

Play/pause, step the rate up or down (1× real time up to a year per second, forwards or back), or type a date to jump. “Now” returns to the present. Everything in the scene moves to match the chosen time.

Scale toggle

Readable compresses distances and inflates body sizes so everything is visible at once. Trueshows real distance and size ratios — on a screen where Neptune's orbit fits, the planets are smaller than a pixel, and Voyager 1 is far out past the edge.

Detail toggle

Switches texture resolution and geometry detail. Drop to Low if the scene runs slowly on your device.

Rings

Toggles the ring systems of Saturn, Jupiter, Uranus and Neptune.

The body list & orbit lines

Groups & search

Bodies are grouped (Planets with their moons nested, Dwarf planets, Asteroids, Comets, Spacecraft). Typing in the search box filters across everything.

Showing/hiding orbits

The eye icon next to each group toggles that group's orbit lines; the eye by the search box toggles them all. Hiding the spacecraft orbits also removes their diamond markers and labels, for a cleaner view.

Lagrange points

Off by default. Enable them in the list to show the Sun–Earth and Earth–Moon L1/L2/L4/L5 points as small diamonds; hover for the name. The James Webb Space Telescope sits near Sun–Earth L2.

Spacecraft

Ten craft are tracked: Voyager 1 & 2, Pioneer 10, New Horizons, Juno, JWST, Parker Solar Probe, OSIRIS-REx, Lucy and Europa Clipper. They show as diamond markers at a distance and swap to a real 3D model when you zoom in close. Each craft's trajectory only covers the span for which Horizons has data — scrub outside it (for example before launch) and the craft hides with a note. The info panel shows its distance from the Sun and Earth and its current speed.

Close approaches

The Close Approacheslist shows asteroids and comets passing near Earth in the next 90 days, with date, miss distance (in lunar distances) and relative speed, straight from JPL's close-approach data. Click an entry to pull that object into the scene, jump time to the moment of closest approach, and focus it. This is informational only — distances and timing, no risk or probability scoring of any kind.

Satellite mode

Zoom in on Earth and a Satellite modebutton appears. It plots Earth-orbit satellites from their published orbital elements: “Notable” (the space stations and the brightest, most recognizable satellites) by default, with GPS, GLONASS, Galileo, BeiDou and Starlink as optional layers. Click a notable satellite for its catalog details — type, operator, launch date, orbital period, altitude and inclination — plus a 3D model for the ISS and Hubble. Satellite positions are only valid near the present day.

Tour mode

Building a tour

Open Tour(near the time controls). Load a built-in preset (Grand Tour, Voyager's Path, Ring Worlds), or click Build and then click bodies to add them as stops. Each stop has a transition time, a hold time, a camera distance, and camera angle (azimuth/elevation). By default the camera frames the sunlit face; the azimuth control lets you rotate to a backlit or side view.

Playback & recording

Play, pause and scrub the tour timeline (this runs on real time, separate from the simulation clock). Press H to hide all on-screen controls for a clean screen recording, and press it again to bring them back. Optional letterbox bars and a live readout (target name, distance, speed) are toggleable. Export a tour to a JSON file to save or share it, and import one back.

Accuracy & disclaimers

I'm aiming to make this as accurate as I reasonably can, but it may not be 100% accurate. Treat it as an educational visualization, not a source for navigation, observation planning, or any operational use. Known limitations:

Planet and small-body positions come from Kepler propagation of osculating elements. That's excellent over reasonable time spans but ignores ongoing gravitational perturbations, so accuracy drifts the further you scrub from the present — most visibly for bodies that have close planetary encounters (some comets and near-Earth asteroids).
Spacecraft and Lagrange points only have data for the window Horizons publishes; outside it they're hidden rather than guessed.
Satellite positions are propagated from recent orbital elements and are only meaningful within a few days of now; they drift quickly and don't model manoeuvres or decay.
Sizes, ring dimensions and rotation are modelled from published values but the visuals are simplified. In readable scale, distances and sizes are deliberately distorted so the system is viewable.
Surface maps and 3D models are representative, and some moons reuse a generic map where no public imagery exists.

Credits

Ephemeris & close-approach data: NASA/JPL-Caltech Horizons & SBDB
Planet textures: Solar System Scope (CC BY 4.0)
Moon & dwarf-planet maps: NASA/JPL-Caltech, USGS Astrogeology, JHUAPL/SwRI (New Horizons), LPI — public domain, via Wikimedia Commons.
Shape models: NASA 3D Resources (Bennu, Eros, Vesta, Phobos, Deimos); 67P shape model © ESA/Rosetta/OSIRIS (CC BY-SA 3.0 IGO).
Spacecraft & observatory models: NASA 3D Resources (Voyager, Juno, JWST, Parker, Pioneer 10, OSIRIS-REx, Hubble, ISS).
Satellite orbits & catalog: CelesTrak TLE and SATCAT data.
Built with Next.js, three.js, and React Three Fiber.

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