Armillary Sphere

An armillary sphere (variations are known as spherical astrolabe, armilla, or armil) is a model of objects in the sky (in the celestial sphere), consisting of a spherical framework of rings, centred on Earth, that represent lines of celestial longitude and latitude and other astronomically important features such as the ecliptic. As such, it differs from a celestial globe, which is a smooth sphere whose principal purpose is to map the constellations.

Read more about Armillary Sphere:  Description and Use of The Armillary Sphere

Famous quotes containing the word sphere:

    A knowledge of the Globe and its various inhabitants, however slight ... has a kindred effect with that of seeing them as travellers, which never fails, in uncorrupted minds, to weaken local prejudices, and enlarge the sphere of benevolent feelings.
    James Madison (1751–1836)