Home SCIENCE Go Inside a Telescope Mirror Factory – To a Billionth of a...

Go Inside a Telescope Mirror Factory – To a Billionth of a Meter


Beneath the University of Arizona football stadium sits the Steward Observatory Mirror Lab. There, giant mirrors are meticulously shaped and polished, to be used in telescopes around the world that are helping unravel the mysteries of the universe.

image/text credit: National Geographic 

The time-consuming production process requires that each mirror’s surface be polished down to a billionth of a meter.Large-aperture telescopes use multiple segmented mirrors, which require grinding and polishing to achieve a specific surface-form.

There is growing demand worldwide for high-precision, nanometer-level control of surfaces to manufacture these mirrors on an increasing scale. However, current production processes are slow.


The largest number of meter-class mirror segments made anywhere for an optical telescope is 36, and these were made by running a prototype manufacturing process 36 times.