München 2019 – scientific programme

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GP: Fachverband Geschichte der Physik

GP 6: Tools and Technologies of physics research

GP 6.1: Invited Talk

Tuesday, March 19, 2019, 14:00–14:45, HS 9

Tools of Physics as Technological Systems: Building Big Telescopes before 1825 — •Richard Kremer — Department of History, Dartmouth College, Hanover, New Hampshire, USA

The classic histories of the telescope credit Fraunhofer with inventing the parallactic mount (the "Fraunhofer" or "German" mount) when in 1824-25 he built the large refractor for Dorpat. Solving a host of mechanical problems, Fraunhofer's design drew wide acclaim and would be widely copied by makers of large refractors for the remainder of century. The success of the German mount provides a central theme in most narratives of telescope history.

In this talk I will reconsider this episode in telescope history by looking not at post-1825 telescope mounts but at pre-1825 attempts to mount telescopes equatorially. Technology historian Thomas Hughes proposed a set of concepts for analysing what he called technological systems. By applying those tools to the history of large eighteenth-century telescopes, I want to look for "reverse salients" or bottle-necks in the system (optics, mounts, operating procedures) that Fraunhofer was trying to remove. Hooke, Sisson, Ramsden, George Adams, Short, Nairne and Troughton had all devised equatorial mounts; Herschel's large reflectors employed alt-azimuthal mounts. How did these eighteenth-century makers and their customers understand the reverse salients in their technological systems? How did Fraunhofer understand those reverse salients? And how did technological systems, astronomical practices and trade secrets circulate across boundaries of nation states, scientific disciplines, and craftsmen's shops? END