Cream metal disc with metal cylindrical protrusion in the middle

Cream metal disc with metal cylindrical protrusion in the middle, associated with the "Twin Equatorial" Telescope, 1885. Made by Sir Howard Grubb, consisting of a 20in. Reflecting Telescope and a 7in. Refracting Telescope (by Cooke) mounted together on one equatorial stand. With Grubb electric control gear

Details

Category:
Astronomy
Object Number:
1936-231/16
Materials:
metal (unknown) and paint
type:
instrument component
credit:
Bower, W.L.N.