The Age of the Great Refractors

Abstract

William Herschel and Lord Rosse might have put their faith in reflectors, but at that period most other people thought differently, and it was the refractor which held sway. This was due largely to the work of Josef Fraunhofer, in Germany, who proved to be a genius at lens-making; it is doubtful whether his object-glasses have been surpassed even now. One of his refractors, an equatorially-mounted 9-inch, had been sent to the Berlin Observatory, and it played a major rôle in yet another curious episode which is very much part of our story.