TWELVE SUMMERS AGO, UNIVERSITY of Arizona astronomer Roger Angel swung by a Tucson pottery shop to pick up some firebricks for a backyard kiln. Then he purchased some glass ovenware at a nearby hardware store. A few days later, he materialized in a graduate student's doorway, brandishing a couple of Pyrex custard dishes melted to a misshapen blob. "We can make telescope mirrors out of this!" Angel exclaimed. Thus began a monumental and quixotic effort to reinvent the central light-gathering surface of the telescope, from its initial design to its final polishing.
This month, many years and millions of dollars later,...