Celestial sphere. North India, ca.1820.

Celestial sphere. North India, ca.1820.
In brass.
Measurements: 15 cm. diameter.

Antique celestial globe from India, with spherical representation of the sky and celestial bodies, such as stars and constellations. These globes, with engravings, inscriptions and zoomorphic and pictographic representations, were historically used to study the relative positions of the stars and for navigation. Unlike globes depicting the Earth, celestial globes show the constellations, stars and other astronomical elements such as the ecliptic (the apparent path of the Sun) and the celestial equator. These objects were not only scientific tools, but could also have significant artistic and cultural value.

In astronomy and navigation, the celestial sphere is an imaginary sphere of arbitrarily large radius, concentric with the Earth. All objects in the observer's sky can be considered as projected onto the inner surface of the celestial sphere, as if it were the lower part of a dome or a hemispherical screen. The celestial sphere is a practical tool for spherical astronomy, as it allows observers to plot the position of objects in the sky when their distance is unknown or irrelevant.