Brass 5" Celestial Spherical Astrolabe or Armillary Sphere
Brass 5" celestial astrolabe on a wooden stand, also called a armillary sphere
An armillary sphere (variations are known as spherical astrolabe, armilla, or armil) is a model of objects in the sky (on the celestial sphere), consisting of a spherical framework of rings, centred on Earth or the Sun, that represent lines of celestial longitude and latitude and other astronomically important features, such as the ecliptic.
The ring is 10cm in diameter. & it stands 12.5 cm tall