What type of machine did Leonardo da Vinci design to polish and shape mirrors?

Leonardo da Vinci designed a mirror-grinding machine to polish and shape mirrors.

Leonardo investigated optical instruments and the production of curved reflective surfaces. His mechanical concepts used controlled motion to grind or polish a mirror more consistently than hand work alone. Such a machine could help produce the precise concave surfaces needed for optical experiments.

The work belongs to Leonardo's broader interest in vision, light, geometry, and mechanical production. He studied reflection and perspective extensively, although he did not build a modern reflecting telescope from these sketches.

A mirror-grinding machine should not be confused with a telescope itself. It is a manufacturing device for preparing an optical surface; the telescope is the complete observing instrument assembled from optical and structural components.