The Great Refractor at Harvard

I had the unique opportunity recently to visit the Harvard College Observatory in Cambridge, Massachusetts. My group enjoyed a star-gazing party on the roof where I saw Saturn and its rings through a telescope for the first time. The highlight was climbing up the steps to see the historic “Great Refractor,” a 15-inch telescope made in Munich and installed in 1847. Sitting under a 30-foot dome, the 20-foot long mahogany tube  reigned for twenty years as the largest telescope in the United States and was among the finest in the world.

Yale University built the first known permanently fixed telescope in America in 1828 and other universities soon followed. Although Harvard University staff wanted to build an observatory as far back as 1815, the costs for construction and operation discouraged serious efforts. A comet in 1843 finally pushed interest in astronomy to a high enough level that a fund drive commenced and ninety-four donors contributed $25,730 to build the observatory. Their names are listed on a marble plaque inside the dome and include President John Quincy Adams. Interesting fact that today the observatory is part of the Smithsonian Astrophysical Observatory – part of the Harvard-Smithsonian Center for Astrophysics. Adams was also influential in the founding of the Smithsonian Institution in Washington.

It’s not hard to imagine excited 19th century astronomers sitting on the padded observing chair (kind of a sofa on a giant suspended roller) gazing into the heavens hoping to make new discoveries. The chair can move up and down to give the observer the proper position at the eyepiece. It was here that astronomers first discovered Saturn’s eighth satellite and observed its inner ring.

Then we went into the stacks and saw a few of the roughly 500,000 astronomical plates, the largest collection in the world.  The collections includes the first daguerreotype of a star and many amazing clear images of the Moon taken from 1847-1852.  We saw one of the earliest images of the Moon and notebooks with sketches by early astronomers. We learned about Annie Cannon and Henrietta Leavitt, originally hired as computers who performed calculations and carefully examined stellar photographs (counted images on photographic plates).  They made pivotal contributions to astronomy: Cannon is credited with the creation of a classification scheme to classify stars based on their temperatures and Leavitt developed a formula that led to a paradigm shift in modern astronomy.

The Great Refractor is only used on special occasions today. It stands as an outstanding example of 19th century scientific achievement.

Read more: New York Times article about the collection of glass plates

About Tim

Author, public historian, and consultant. Author site: - My fifth book, Star Spangled: The Story of a Flag, a Battle, and the American Anthem, was published in May 2020. Consulting site: I specialize in exhibition development, interpretive planning, education strategy, and history relevance. I'm passionate about helping history organizations of all sizes and kinds make history more relevant for their communities and the people they engage with. I'm happy to consider many types of writing projects for informal learning organizations. Reach me at or
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1 Response to The Great Refractor at Harvard

  1. Pingback: History – Sophia's Final Major Project

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