Man has always been fascinated by observation of the universe, and has interpreted it in various, often highly imaginative, ways. In the 17th century, the Scientific Revolution led to the construction of three-dimensional models of the celestial vault and the Earth, of which some still survive.
Terrestrial globes showing continents, seas and oceans represent the known world at the time they were made.
Armillary spheres composed of circular strips of wood or metal generally represent the planetary system composed of the Earth, Sun, Moon and the known planets, in two different versions: the geocentric model and the heliocentric model.
The geocentric model developed by the Greek astronomer Ptolemy in the 2nd century AD – which features the Earth at the centre of the universe with the Sun revolving around it, in accordance with the Aristotelian vision of the world – was almost universally accepted until the end of the 16th century.
The heliocentric model proposed by the Polish astronomer Nicolaus Copernicus (1473-1543) in his work De revolutionibus orbium coelestium, placed the Sun at the centre of the universe with all the planets rotating around it. Although it explained the planets’ motions in a simpler way than the Ptolemaic system, the model was opposed by the Church and De revolutionibus was subjected to censorship until 1757.
Their use facilitates an understanding of natural phenomena and helps to solve questions regarding the rising and setting of the Sun or the determination of its height in a given place on a certain day of the year. The numerous astronomy treatises of the 17th and 18th centuries list a series of problems that can be solved by using astrolabes and globes.