Astrolabium

From the Introduction:

Hidden deep underground lies this mystical astrolabium, channelling arcane energies to simulate the celestial bodies moving across the skies far above in astonishing detail. Three massive crystal lenses that can be rotated in every direction on a metal frame focus the arcane energies flooding through the room into its centre to manifest them as models of celestial bodies. The rooms floor is wrought of finely polished marble. And lecterns of root wood, polished to a sheen, surround the magical aperture dominating the room. A single doorway breaks the spherical wall of the room which is plated in metal to prevent disruptions from the outside.