The spherical astrolabe, also known as the armillary sphere, is an ancient astronomical instrument used to represent and study the movements of celestial bodies. Unlike the planar astrolabe, which is a two-dimensional representation of the sky on a disk, the spherical astrolabe consists of a series of graduated rings representing the main circles of the sky, such as the celestial equator, the tropics, and circles of altitude and azimuth, all mounted within a sphere symbolizing the Earth at its center.

The presented item is a wooden model of a spherical astrolabe used by Nicolaus Copernicus to observe the sky. The instrument was crafted based on the description provided in De revolutionibus orbium coelestium. It consists of six concentric wooden rings equipped with angular scales. These types of astrolabes were used to determine the ecliptic coordinates of the planets and the Moon, as well as to establish local time.

Marcin Banaś (Museu da Universidade Jaguelônica, Collegium Maius)