Armillary sphere for astronomical measurements and teaching - has rose with twelve sectors, rotatable about meridian, and double crown for elliptic motion

摘要

The armillary is formed of a rose, an armilary sphere and a supporting foot. The rose has twelve sectors at the centre of which is a terrestrial globe able to move around its polar axis. The sectors are able to pivot around the local meridan. The armillary sphere has a triple ring for the celestial equator which can receive two semi-great circles representing the plane of the galactic equator and a plane where one measures declinations. It also has a double ring for the ecliptic which is able to turn around an axis perpendicular to the plane of the celestial equator and can receive a semi-great circle where one measures celestial latitudes. The support foot is provided with an index I situated in the plane of the meridian. The instrument allows visualisation of the relative positions of the horizon, of the local meridian, of the celestial equator, of the ecliptic and of the plane of the galaxy.