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 on wikipedia.
Celestial sphere. European celestial globe (view 2), 1878. This globe features beautiful constellation figures such as Taurus the Bull and Aries the Ram. The star patterns are the reverse of what we see in the night sky, because many celestial globes depict the sky as if you were outside a sphere, looking down.