Astronomical calculators and graphical computers — computing without numbers
Before silicon chips and digital displays, humanity built extraordinary mechanical and graphical devices to compute the positions of planets, tell time by the sun, and solve complex equations with nothing more than nested rings, spinning discs, and parallel scales. These instruments represent centuries of ingenuity — each one a testament to the idea that understanding the cosmos requires not just observation, but calculation. Explore six landmark instruments that changed how we measure and predict the heavens.
Ancient and medieval devices for tracking stars, planets, and the mechanics of the heavens.
Nested celestial rings — ecliptic, equatorial, meridian, and horizon — rotating around Earth. Drag to explore the ancient model of the cosmos.
Clockwork planets orbiting the Sun at correct relative speeds. Visible gears show the mechanical linkage underneath. Control time to watch the dance.
A disc-based planetary calculator using Ptolemaic epicycles. Set the date, rotate the discs, and compute ecliptic longitude without arithmetic.
Ingenious devices that replaced complex formulas with visual alignment and the motion of shadows.
Parallel-scale calculators for multiplication, BMI, and Ohm’s law. Drag the straightedge across scales to read answers at intersections.
Multi-dial clock showing time, calendar, solar and lunar positions, eclipses, zodiac, and animated automata. Fast-forward time to watch it all.
Set latitude, date, and orientation to cast realistic gnomon shadows onto hour lines. Compare solar vs. clock time with analemma display.