Orrery is an educational model, not a navigation or observation-planning tool.
One clock. Two motion models.
Mechanical connects the crank to successive compound gear reductions, coaxial output sleeves and keyed planet arms. The fixed integer tooth ratios approximate mean orbital periods; the arms follow circles. Their starting directions are indexed once at J2000. This is a kinematic exhibit, not a manufacturable clock: tooth flanks, tolerances, friction, torque and dynamics are not engineering-validated. The Follow the drive readout gives each selected output’s route and period error.
Observatory retains the JPL approximate orbital shapes, inclinations and varying speeds. Switching presentations can therefore change planet positions. The Sun-distance readout always belongs to this astronomical reference, not to the geared arm geometry.
Scale, made explicit.
Display scale compresses orbital spacing and enlarges bodies so the whole system can be explored. True distance uses one distance scale in Observatory; planet and Sun sizes remain enlarged. Surface detail and lighting are illustrative, not a live image. Earth’s globe follows approximate date-driven solar geography; other planetary attitudes remain illustrative. None is a calibrated rotational ephemeris.
Sunlight & Earth orientation
Lights out removes the exhibit lights and environmental fill, leaving sunlight on the worlds and ordinary model shadows from the moons. Uncheck it to restore the exhibit. Machinery becomes a silhouette, not a newly sunlit mechanism. Thin Saturn rings receive shadows but do not cast them, avoiding aliasing from their closely spaced bands. Shadows use enlarged bodies and illustrative moon orbits: they do not predict eclipses, paths, penumbrae or lunar reddening.
Earth’s existing map turns with the selected UTC date in both presentations. Its free visual tilt is adapted to the displayed Sun, not transmitted through the gearing; machinery and orbital rates are unchanged. The NOAA/Meeus solar approximation is used across 1800–2250. UTC stands in for astronomical time scales; this is approximate solar-relative geography, not precision body attitude. If the Earth image fails to load, its procedural fallback is not georeferenced.
Surface imagery & attribution
Planet and Sun maps by Solar System Scope, licensed CC BY 4.0. These NASA-imagery-derived maps use adjusted colors and fill unmapped regions artistically. Inspector portraits are spherical projections with illustrative shading and orientation, derived from these same maps. Pluto is procedurally illustrated. Full attribution.
Ten selected moon companions
Earth’s Moon, Io, Europa, Ganymede, Callisto, Enceladus, Titan, Miranda, Triton and Charon use sourced physical properties. In Mechanical, solid PVD support bars carry the planets; slender nested sleeves carry the small moon arms and globes. Separate shafts and enclosed lunar reductions follow the shared crank ratios. These internal reductions and right-angle transfers are schematic: their gears are not modeled, and fitting them inside the slender supports has not been engineering-validated. In Observatory, moons follow the separate simplified circular calculation. Starting phases and orbital planes are illustrative, not observed positions. Local spacing and sizes are enlarged independently, even in True distance mode; mechanical families are spaced to reserve their swept clearances. Their surfaces are original illustrations with exaggerated features, not georeferenced maps.
Open a planet’s Moon companions panel and choose a named moon to inspect it. Inspection preserves playback and follows the subject’s position without following its rotation. Orbit and zoom remain available; panning releases the camera. Charon’s Pluto-centered display does not model the system’s barycenter.
JPL: Satellite mean elements ↗
Materials & construction
The lower gear bank has a black DLC material treatment; planet and moon support arms use polished black PVD. Blue-fire black-opal inlays adorn the pillars, fit within the original pivot openings and cap the crank grip. The pivot housings, arms and gearing are unchanged. These are original physically based material studies, not measured coating or gemstone scans. Saturn’s independently colored bands interpret Cassini natural-color imagery, with exaggerated gaps and no calibrated photometry.
Scientific reference
The astronomical model and supported date range will appear here when the instrument loads.
JPL: Approximate positions of the planets ↗
Designed for exploration
Drag to rotate; scroll or pinch to zoom. Select planets using the row below the instrument. Pause to study a moment, change the date, or reverse time. Sun distance and the orbit descriptors are approximate. The background stars are decorative, not a sky catalogue. Reduced-motion preferences start the instrument still. All numerical properties are available outside the 3D view.
Open source & privacy
Original Orrery code is MIT licensed. Planet maps, fonts and brand marks retain their separate terms; see credits and licenses. Source code & documentation ↗.
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ProDyn.ai · Orrery v0.6.0 Beta 1 · Made by Promethean Dynamic Nerdiness
