John Brashear, standing next to the coal shed where he first began work on telescope lens in the early 1870s, Pittsburgh, PA, 1913.

Credit: From the Collections of the Pa. Dept., The Carnegie Library of Pittsburgh.

A Pittsburgh machinist with little formal education, John Brashear spent years figuring our how to grind telescope lens of extraordinary precision. Brashear would go on to produce some of the best telescopes of his era, and become a prominent astronomer.