From the Celestial Globe to the Astrolabe Transferring Celestial Motion onto the Plane of the Astrolabe

Abstract

Abstract The celestial globe is an early astronomical instrument that gives a realistic view of the heavens and the stars and can simulate the celestial motion, but has some disadvantages such as difficulties in construction, transportation and in carrying out measurements. The astrolabe is an evolution of the celestial globe; it represents the celestial sphere projected onto the plane, retaining the celestial ratios. It provides accurate measurements and helps in solving a great variety of astronomical problems. The aim of this paper is to show how various processes have been transferred from the celestial globe to the astrolabe, determining the form of each part of the astrolabe.