On Tycho's Island: Tycho Brahe and His Assistants, 1570-1601John Robert Christianson
Cambridge U. Press, New York, 2000. $34.95 (451 pp.).Reviewed by Mary Lou West
John Robert Christianson contends that Tycho Brahe invented "big science" when, in the late 1500s, he developed the research complex Uraniborg on the island of Hven in Copenhagen Sound. On Tycho's Island convincingly supports this thesis by providing long lists of people who worked there, instruments they designed and used, their observational protocols, and their methods of data reduction. The complex was the site of many chemical, medical, map-making, printing, and waterworks activities, as well as the astronomical observations of the positions of planets and comets for which Brahe is justly famous. King Frederick II of Denmark supported the institution financially because of the international prestige it garnered and the increased educational opportunities it made available to his subjects.
Christianson shows how a summer on Hven became an expected capstone of a European college education, and students arrived in groups of 5-10, rather like an early REU (research experience for undergraduates) program. Graduates and postdocs signed contracts to work there for one to five years in return for room and board and an annual suit of clothes. If they were useful, then Brahe brokered permanent jobs for them at schools, parishes, or universities in a well-established patronage network. Most of these young men (and one woman) were aristocrats, but some were bright farm boys. Brahe's chief assistant, Christian Longomontanus, the son of peasants, probably would have succeeded him as imperial mathematician at Prague if he, rather than Johannes Kepler, had been present at Brahe's death.
The book describes the path from astronomical determinations of latitudes and triangulation measurements to the first accurate maps of many regions of northern Europe. Brahe often sent young colleagues out as couriers with letters, scientific papers, poetry, and mechanical devices as gifts to important people in the patronage network, making measurements of latitude with portable sextants wherever they went. One of the first scientific expeditions of modern times was Elias Morsing's journey in 1584 to determine the exact latitude of Copernicus's observatory, so that his data could be combined with recent measurements from Uraniborg.
Christianson describes Brahe's legacy as his empiricism, his methods of observation with errors determined, and his mathematical data analysis, including an early form of logarithms. Although he was Tycho Brahe's heir, Kepler was not interested in organizing large-scale projects. Twenty-six years after Brahe's death, he published the Rudolphine Astronomical Tables, which enabled astronomers to calculate planetary positions for any time in the past or future. Thereafter, "aristocratic big science gave way to a brilliant scattering of individualized science by middle-class scholars."
As a nonspecialist reader, I longed for a handy map of Denmark with places like Skåne, Ribe, and Stjernholm marked, and also for a large map of northern Europe, so that I could better picture the travels of Brahe's wagon entourage from Rostock to Wandsburg to Prague, after his self-exile from Denmark. Since much of the patronage system of those days depended on links to relatives, a chart of the extended Brahe-Bille-Rosenkrantz family would have been useful too, and a graphic timeline of these people's comings and goings to Hven could have been illuminating. A short discussion of Brahe's lunar and solar theories as they evolved would also have been appreciated. Christianson said his overflowing shoebox database of Brahe's coworkers prompted him to publish this compilation before he retired from Luther College in Iowa. I hope that someone else will carry on the work, as he suggests. These interesting stories cry out for a better integration.
On Tycho's Island brims with intriguing material, including 53 pages of footnotes and references that could have been presented better (unless the only intended audience is other historians). The general reader might best read the first few pages of each chapter, then skip to the last third of the book, which contains lively short biographies of the individuals who worked with Tycho or visited Hven. The 1990 book by Victor E. Thoren and Christianson, The Lord of Uraniborg (Cambridge U. Press), remains the best biography of Tycho himself.