Lens

Johannes Hevelius (1611-1687) is justly famous as an astronomer, but his livelihood came from the family’s brewing business, and Johannes himself was admitted to the Brewer’s Guild in 1636. His interests lay elsewhere, however. Devoting himself to constructing astronomical instruments and, most importantly, to carefully and precisely grinding lenses for telescopes, he developed an extremely well-equipped 17th-century observatory in Danzig, Poland.