Bill Donahue clearly loves to talk about working with the newest piece of scientific equipment at St. John’s College, even though it’s not high tech.
“Nobody has done this for 300 years,” he says of scanning the skies through an eight-foot-tall equatorial armillary sphere that was recently installed in a courtyard at St. John’s Santa Fe campus.
Donahue, a retired faculty member and director of laboratories at the college, explains that the device was commissioned based on a designs from a 1598 book by groundbreaking Danish astronomer Tycho Brahe.
Brahe was moving from Denmark to what’s now the Czech Republic and wanted to document his instruments. And this was a decade before Galisteo invented the telescope. “This thing provided the missing link,” said Donahue.
Now, St. John’s armillary sphere is the only one like it in the world. None of Brahe’s originals survive.
Donahue said Brahe managed to make dramatic improvements in measuring the positions of stars and planets with his devices. The dumbed-down version of how it works it that it measures where along and how far north or south of the equator a celestial body is. “His measurements were 10 times more accurate than anything before,” Donahue said.
That kind of information helped advance the science of astronomy in many ways, he said. Johannes Kepler, for instance, used Brahe’s coordinates show that Mars revolved around the sun in an elliptical orbit, disproving the long-held theory of circular movement of heavenly bodies.
So why does St. John’s have a Brahe’s sphere made from surgical stainless steel? Donahue said that each graduating class at the college undertakes a project to benefit the school, and the class of 2004 decided that what the campus needed was an armillary sphere.
He called that decision a very St. John’s thing to do, a reference to St. John’s classical curriculum.
More than $100,000 was raised and British craftsman David Harber was commissioned to build the thing. Donahue and Harber consulted each other on making sure the finished project was precisely correct.
Brahe left only a brief description of how to use the sphere. “The best way to learn is to use it,” said Donahue.
At St. Johns, the device will allow students to go beyond the mathematical and abstract, and observe the planets as they move, he said.
“Historical scientific instruments are fundamental to learning at St. John’s,” the college said in fact sheet about the class of 2004’s bequest.
“It has raised the bar on how senior classes think about their class gifts.”