In Search of a New Historiography of the Telescope

Abstract We seek a new historiographical perspective on attempts to understand and improve the performance of the telescope in the first half of the seventeenth century. The invention of the telescope in the early seventeenth century presented natural philosophers, mathematicians, and practitioners with opportunities and a significant challenge. Examining contributions ranging from Galileo to Christoph Scheiner, we argue that their work exhibits different responses to the difficulty of rendering the telescope reliable, controllable, and capable of improvement despite the absence of a shared theoretical understanding of the instrument. Our paper then is a study in the dynamics of practice and theory. Throughout this period, a persistent tension existed between perspectival optics and workshop practice. Geometrical relations increasingly served as operative means for regulating and improving telescope performance as well as for explaining optical behavior. This instrumental orientation was articulated explicitly by Carlo Antonio Manzini, whose retrospective account of telescope-making procedures throws into relief the practical domain on which future physical theories of optical instruments would be based.