Ptolemy’s Armillary Sphere The armillary sphere is the earliest known type of astrolabe. It was used as early as the 2nd century AD by the astronomer and mathematician Claudius Ptolemy of Alexandria. Ptolemy’s armillary astrolabe represented the main celestial great circles with connected, pivoting, graduated bronze rings. Read more about Ptolemy’s armillary sphere in the Clocktime article The first timekeepers: telling time before the pendulum clock. Image Credits Ptolémée, 1475 / 1500 (4e quart du XVe siècle) Gand, Juste de Berruguete, Pedro Pays-Bas du Sud, Musée du Louvre, Département des Peintures, MI 657 - https://collections.louvre.fr/ark:/53355/cl010064735 Ptolemaic armillary sphere. Full view, graduated matt black perspex background. Ptolemaic armillary sphere, Unknown, 1501-1600, Science Museum Group Collection © The Board of Trustees of the Science Museum, CC BY-NC-SA 4.0, https://collection.sciencemuseumgroup.org.uk/objects/co56290/ptolemaic-armillary-sphere-armillary-sphere Ptolemaic armillary sphere. Detail view, graduated background. Ptolemaic armillary sphere, Unknown, 1501-1600, Science Museum Group Collection © The Board of Trustees of the Science Museum, CC BY-NC-SA 4.0, https://collection.sciencemuseumgroup.org.uk/objects/co56290/ptolemaic-armillary-sphere-armillary-sphere
