History of the Washburn Observatory in Madison, WI


The observatory circa 1885. | Photo via Wiki Commons

Tucked away on the UW-Madison campus lives a relic of the 19th century — the Washburn Observatory. Or, if you’ve lived here long enough, the “Old Observatory.”

History: In 1877, university president John Bascom announced the construction of an observatory with a telescope larger than Harvard’s 15-inch refractor. The observatory’s namesake comes from former governor Cadwallader C. Washburn, who gifted the university a private donation for the building’s construction above Lake Mendota.

Importance: At the time, Washburn was one of the most important astronomical centers west of the Appalachian mountains. The telescope was the third-largest in the nation at the time of production — behind the Naval Observatory and Dearborn Observatory. It was also responsible for setting time for the City of Madison with three pendulum clocks.

Scientific discoveries: Under director Joel Stebbins in 1922, the science center pioneered work on photoelectric photometry and the study of variable stars. His successor, Alfred Whitford, worked on the development of photometry — astronomy by recording amplified light. Or, detected the light of a candle from over a mile away.

Over the years: In 1958, a new observatory was built in Cross Plains by the University of Wisconsin as city expansion interfered with the Washburn’s site. With updated instruments, Pine Bluff Observatory replaced Washburn as the main observatory in the area. Washburn’s dome was refurbished in the 1990s with more updates in 2009.


The observatory as it stands today. | Photo by @scott.jones618

Today: The College of Letters and Science Honors Program calls the space home today. Introductory astronomy courses get to try their hands at the telescope, as well as the public during viewing times. Madisonians are also able to visit on the first and third Wednesday of every month + every Wednesday in June through August, as set forth by Washburn himself.

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