How the Van Vleck Observatory reflects environmental conditions

Before Van Vleck was completed in 1916, Wesleyan’s “observatory” was a tower mounted on a dormitory, containing few instruments with little research capability. Prior to that, the university’s effort at a building devoted to astronomy was little more than a shed.

Professor John Monroe Van Vleck, who taught astronomy at Wesleyan for 50 years, believed the university could do better. He envisioned an observatory with the facilities necessary to make an impact on the world’s understanding of the universe. In 1903, Van Vleck’s family donated more than $25,000 to the university for a new observatory and planning began, but Professor Van Vleck passed away before he could see his vision come to life.

In his stead, Wesleyan’s president Stephen H. Olin entrusted Frederick Slocum, the new astronomy professor, with supervising the observatory’s design. Slocum began a detailed correspondence with Henry Bacon, the architect charged with designing the observatory, to recommend the location, design, and technology of the building. Slocum was as determined as Van Vleck had been to see the Wesleyan observatory contribute valuable research to the scientific community. He was aware that it would not be easy, as New England’s cold, wet, and changeable climate was not ideal for astronomical observation. Slocum used a number of means—geographical, architectural, and technological—to overcome the challenges of doing astronomy in the relatively poor observational environment of New England.

Using local geography

Professor Slocum sought to use local geography to overcome the environmental obstacles to observation. In the 19th century, many of the world’s most successful observatories were placed on mountaintops to be free of visual obstructions. The need for height was a reflection of the limited technology available at the time. Telescopes did not have the enormous magnifying power they do today, so it was all the more important for an observatory’s location to provide a clear view. This was especially true of New England, where the atmosphere is rarely steady or clear enough for accurate readings. Rainfall, cyclonic storms, and cloud cover often prevent observation. Wesleyan’s previous observatory relied on its height to grant a good view in these unfavorable conditions.

Slocum, however, resolved the problem not with a tall building but with a modest building on a tall hill. Slocum recommended that Bacon place the observatory on the crest of Foss Hill. It may not be a mountain, but Foss Hill is the highest point on the Wesleyan campus, allowing the observatory a view over campus and town. The advantages of the location were not fleeting. Though Middletown and the Wesleyan campus continued to develop throughout the 20th century, Foss Hill still elevated the observatory above the new buildings.

Slocum worked with Bacon to site the observatory at the highest point on the Wesleyan campus, the crest of Foss Hill. This 1958 image shows the remove at which Van Vleck sat from the center of campus prior to the construction of the Foss Hill dormitories in the 1960s. Vertical Files Photograph Collection, Box 38, Folder "Van Vleck Observatory -- Photos," Special Collections & Archives, Olin Library, Wesleyan University.

Slocum worked with Bacon to site the observatory at the highest point on the Wesleyan campus, the crest of Foss Hill. This 1958 image shows the remove at which Van Vleck sat from the center of campus prior to the construction of the Foss Hill dormitories in the 1960s. Vertical Files Photograph Collection, Box 38, Folder “Van Vleck Observatory — Photos,” Special Collections & Archives, Olin Library, Wesleyan University.

Architectural strategy

Having successfully employed the local geography to benefit the observatory, Slocum turned to architectural means to adapt it to New England’s uncertain stargazing climate. The professor looked to observatories in the same climate region as Wesleyan for designs to emulate. He noted that, despite the problematic temperature fluctuation, humidity, and cloudiness of the Northeast, the observatories at Harvard and Brown had been highly successful. Slocum attributed a large part of this success to the buildings’ designs. The two observatories each boasted a dome adjoining a flat-roofed building so astronomers could enjoy the benefits of each structure.

Domes are frequently used for observatories because they neutralize the surrounding climate to make visual conditions more favorable. They also improve visibility and allow airflow that regulates temperature and humidity, keeping instruments safe from the cold, wet New England weather that can harm astronomical tools. The velocity of wind must change when it encounters an obstruction, creating layers that distort light, but wind passes by a dome much more easily than it does a wall. A dome can allow visibility of celestial bodies a full magnitude fainter than can be viewed in a flat-roofed building with the same instrument.

But a flat roof is not without its merits. Slocum desired that Wesleyan’s astronomy building have a section of flat roof like the observatories at Brown and Harvard, to allow scientists to step out of the dome for a panoramic view of the heavens. In addition, a rectangular section would provide the space necessary for astronomers to analyze the observations made in the dome. The dome-and-flat-roof design Slocum favored was popular on the east coast for a reason: it allowed observatories to further adapt to the set of environmental conditions of the region and time.

The Van Vleck Observatory circa 1920, shortly after its completion. Vertical Files Photograph Collection Box 38, Folder "Van Vleck Observatory -- Photos," Special Collections & Archives, Olin Library, Wesleyan University.

The Van Vleck Observatory circa 1920, shortly after its completion. Vertical Files Photograph Collection, Box 38, Folder “Van Vleck Observatory — Photos,” Special Collections & Archives, Olin Library, Wesleyan University.

Technical solutions

Slocum then turned to technology to adapt the Wesleyan observatory to environmental conditions. He determined that the university, constrained by a small budget, faced two options in purchasing instruments. They could either buy a few small instruments or use all the money allotted for technology on one enormous telescope. Slocum believed that while the first option might sound more practical, small instruments would not have the capacity to pierce the thick, murky atmosphere of New England. He advocated the purchase of the best single telescope that the fund could supply.

To afford the mammoth instrument, Slocum and Bacon cut the budget in other areas and asked for more donations. Thanks to these efforts, in May 1914, they were able to afford a refracting telescope with an 18.5-inch lens. The lens arrived late because of the First World War; and due to a mistake from the manufacturers, the lens was even bigger than promised at 20 inches.  This proved even better for adapting to the region’s atmospheric and environmental conditions.

Frederick Slocum sits at the 20-inch refracting telescope around which the observatory dome was designed. Vertical Files Photograph Collection, Box 38, Folder "Van Vleck Observatory -- Photos," Special Collections & Archives, Olin Library, Wesleyan University.

Frederick Slocum sits at the 20-inch refracting telescope around which the observatory dome was designed. Vertical Files Photograph Collection, Box 38, Folder “Van Vleck Observatory — Photos,” Special Collections & Archives, Olin Library, Wesleyan University.

Henry Bacon incorporated each of Slocum’s recommendations into the observatory’s design. When it was completed in 1916, some citizens of Middletown complained that it looked like a beehive and stood out like a sore thumb. Little did they know that every aspect of the building was purposeful, planned by Slocum and implemented by Bacon. In a climate too wet, windy, and changeable to reliably produce clear observations, Professor Slocum found creative solutions. He used geography, architecture, and technology to adapt to the environmental conditions of the region and period, creating an observatory that, in 1916, brought John Van Vleck’s dream to life. The Van Vleck Observatory continues to do so one hundred years later.

 

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