30,000 km/s

300,000 km/s

30,000 mi/ s

300,000 m/s

The bands around it pivot on a common center and illustrate the paths of the sun and moon, known planets and important stars.

The first telescope used a combination of two lenses within a tube, and it could magnify items by three times, but showed them upside down.

With such information, the user could make astronomical measurements and tell time.

During the day, a person could tell time with this pocket-size device by unfolding a gnomon, a vertical shaft, and thereby turning the device into a small sundial.

Galileo Galilei invented the geometric and military compass. It was his first commercial scientific instrument.

During the day, a person could tell time with this pocket-size device by unfolding a gnomon, a vertical shaft, and thereby turning the device into a small sundial.

At night, this small device could be used as a nocturnal to tell time. During the day, it could be used as an horary disk to tell time and also to determine when the sun and moon would rise and set.

A portable astronomical calculator that could show how the sky would look when standing at a particular place at a particular time.

A portable astronomical calculator that could show how the sky would look when standing at a particular place at a particular time.

A user could determine the distance of a faraway point by taking measurements from two locations and then using simple geometry.

The device, which resembled two rulers that moved over a third, curved piece, acted as an early calculator.

This extremely rare sundial, also known as the navicula de Venetiis, or “little ship of Venice,” was named for its boat shape.