Guest blog: Seagrave Memorial Observatory centennial (1914-2014)

Posted by Michael Bakich
on Tuesday, July 22, 2014

Recently, David A. Huestis, Historian of Skyscrapers, Inc., sent in a blog about a century-old observatory. It’s a fascinating story we want to share with you.

Frank Evans Seagrave began construction of his observatory in 1914. // All images: Skyscrapers, Inc.
Skyscrapers, Inc., the Amateur Astronomical Society of Rhode Island, is proud to announce the celebration of the 100th anniversary of Seagrave Memorial Observatory on Peeptoad Road in North Scituate during our annual AstroAssembly convention, September 26 and 27. The former observatory of Frank Evans Seagrave (1860–1934), a famous Providence astronomer, has been under the stewardship of the society since the group purchased it in 1936.

The back story
In 1876, Seagrave’s father ordered an 8-inch (clear aperture) Alvan Clark refractor as a present for his son’s 16th birthday. Two years later, the telescope was delivered, and an observatory was built in the backyard of the family residence at 119 Benefit Street in Providence, Rhode Island.

This great instrument was then the third-largest in New England and the largest in private hands in the area. The telescope was mounted in May 1878. Present at the dedication ceremony was none other than Alvan G. Clark, the famous telescope maker. Also present was Leonard Waldo, assistant director of Harvard College Observatory under Edward C. Pickering, who thought the “complement of accessories attending the telescope could occupy the time of two competent observers.”

For many years, Seagrave conducted serious scientific observations from his magnificent facility, including measurements of Saturn’s ring system, comets, asteroids, novae, and variable and double stars. (In fact, Seagrave was awarded an honorary degree from Brown University in 1911 for his orbital calculations on Halley’s Comet.)

However, the installation of street lamps began to affect Seagrave’s observations. A comprehensive article in the Providence Sunday Journal on October 10, 1909, featured a glimpse into the deteriorating observing conditions from his Benefit Street observatory: “Near the observatory, close to Bowen Street, are three large wooden structures which look exactly like the billboards which occasionally ornament vacant lots. These also have come in for their share of comment. One man stopped and looked at them earnestly. Then he said to a companion, ‘This ain’t no sort of place for them big billboards; no one ever comes down this street to look at ’em!’”

“These billboards are screens placed by Mr. Seagrave to keep the light of the street lamps from shining in the observatory and interfering with his observations of the heavenly bodies. It is, he says, at the best of times not good ‘seeing’ in Providence, nor anywhere along the Atlantic coast.”

Another reference noted that the coal dust hung over the city of Providence like a pall, also affecting the local seeing conditions. However, it wasn’t until February 1914 that Seagrave put his instruments into storage and a month later began to look for a piece of property to relocate.

Seagrave (far right) and a group of friends observed the January 24, 1925, total solar eclipse from the now completed observatory.
Seagrave found some land on what is now Peeptoad Road in North Scituate, where he constructed a new observatory and moved his 8-inch Clark refractor there in October 1914. A Providence Journal article on October 12 titled, “Seagrave Observatory is Nearly Complete: Telescopes Now Being Adjusted at North Scituate Building,” provided an update on the work of setting up the telescope: “Frank E. Seagrave has practically completed his astronomical observatory at North Scituate. The building has been finished for some time and his telescopes, which have been moved from his former observatory on Benefit Street, are mounted upon their cement foundations.

“The adjustment of the two telescopes, one of 8½ and the other 3-inch diameter, has been in process since the first of the month. This delicate task is now finished, except the adjustment of the instruments to altitude and azimuth.

“Mr. Seagrave finds conditions at North Scituate ideal for the purpose of astronomical observation. The view is sweeping and unobstructed and there is an entire freedom from reflected light which is always a serious hindrance to accurate observation from points within the limits of cities. In this respect, the new observatory possesses great advantage over the former location on Benefit Street.”

In 1925, Seagrave made a key observation of the January 24 total solar eclipse. The group observed totality for just five seconds, thereby defining a northern limit for the path of totality. Seagrave continued his research until his death in 1934.

Skyscrapers acquire observatory
Skyscrapers, founded in 1932 by Professor Charles Smiley of Brown University, purchased the facility in 1936. After some needed repairs, Skyscrapers held their first “open night” January 15, 1937. This tradition continues to the present day, with the facilities open every clear Saturday night for public viewing.

Throughout the years, Skyscrapers continued to maintain Frank Seagrave’s beloved observatory. However, in the middle to late 1960s, the observatory fell into a state of disrepair, and major upkeep was lacking. Fortunately, a new generation of young astronomy enthusiasts sparked the revival of Skyscrapers, which in turn helped initiate the resurrection of the observatory. The younger members had the energy and desire to make the necessary repairs to keep the observatory and Clark refractor in decent working order.

In 1976, it was necessary to completely renovate the dome. Although the deteriorating exterior plywood was removed, the underlying wooden supports that formed the cylindrical structure were sound. Sheets of corrugated fiberglass, a much lighter choice of material than any wood product, were fastened to the support structure.

In addition, the society needed to solve a recurring problem. The observatory rotated on seven 5½-inch-diameter Civil War vintage cannon balls. These bearings, contained by conduit bent around them, were sandwiched between two well-greased curved cast iron tracks. The problem was that the wood beneath the bottom track was rotting away. This fact caused a cannon ball to bind when it encountered a lip at the joint where two sections of track met. The operator could not deliver enough torque to the wheel that turned the dome to get the ball up and over the bump. The result: the dome jammed. Whenever that happened observing, was over for the evening.

Furthermore, a more serious and rare side effect could also occur. Just before jamming, a cannon ball could pop out of its conduit. If it hit the floor, everything was fine. This incident happened only once. No member or guest was ever injured due to this freak scenario.

The solution came to member and engineer Steve Siok, who was inspired by the 1976 Summer Olympics held in Montreal. He was watching a track and field event when the idea came to him. The dome’s cannon balls could be replaced by fifteen 16-pound shot puts, each within a ball cage and spaced equidistantly on the track. This dome work was carried out and completed during the summer of 1976.

While most, if not all, earlier repairs or renovations were made at Seagrave Memorial Observatory by Skyscrapers members under the direction of the board of trustees, a contractor was hired in 1980 to replace the observatory roof and slit. And several times in the 1980s, the observatory deck was replaced.

The 8-inch Alvan Clark refractor, now completely restored, is the main instrument at Seagrave Memorial Observatory.
In November 1991, Skyscrapers acquired a grant to make major renovations to the observatory building. A second grant was awarded in November 1993 because there was still work to be done to the brick structure of the observatory. (The mortar was falling out and could be removed by using one’s fingers.)

To prepare for the major re-pointing necessary to guarantee the structural integrity of the building, the entire brick structure was sandblasted and power-washed inside and out. (Interestingly, the silo-shaped structure is composed of two concentric brick walls). A number of the original window openings were bricked over for security, and re-pointing proceeded. The final step involved coating the bricks with a sealant.

A portion of a final grant in November 1999 was used for further repairs to the dome. The observatory floor and deck were replaced, and repairs were made to the observatory dome roof and observing slit once again. As Skyscrapers headed into the new millennium, the observatory building looked and operated as it must have back in 1914 upon completion of its construction.

However, there was still more work to be accomplished to return Seagrave’s observatory to its original condition. That task involved the reconstruction of the clock drive and the restoration of the Clark telescope.

The original flyball governor, an integral component of the weight-driven clock drive, was destroyed by vandals in October 1974. Beginning in 2003, Skyscrapers member Al Hall, armed with only a few remaining parts for scale, some 1960s vintage photos, and a lot of research, designed a replica of the governor using CAD software. The parts were then fabricated and assembled. Additional photos, which were discovered much later during the project, revealed how the weight drive was installed. After testing and minor modifications, the completed drive was re-dedicated July 11, 2009.

Soon thereafter, permission was granted from the trustees to undertake a complete restoration of the Clark refractor itself. Under the direction of Al Hall and Dick Parker, with the help of about a dozen Skyscrapers members, the telescope was completely disassembled and each part carefully cataloged, measured, and meticulously cleaned.

The brass was lacquered to prevent oxidation, and the metal tube was painted brick red. During September 2010, the telescope was reassembled. The restored telescope and accompanying replicated flyball governor and weight-driven clock drive were as pristine as the day they were delivered to the Seagrave residence in 1878. At last the society could concentrate on fulfilling its mission to educate members and the public on the science of astronomy.

Today, Seagrave Memorial Observatory is open to the public on all clear Saturday nights.
Frank E. Seagrave would be pleased to know that his beloved observatory on Peeptoad Road is still functional a century after its construction. The Skyscrapers organization takes pride in its stewardship of this beautiful facility. Future generations of amateur astronomers and the public alike will have access to a well-maintained Alvan Clark refractor and a magnificent observatory thanks to the hard work and dedication of the members of Skyscrapers, Inc., The Amateur Astronomical Society of Rhode Island.

This article is dedicated to all past and present Skyscrapers members who have devoted their time and effort to preserve this lasting legacy and tribute to Frank Evans Seagrave. Explore in detail the rich history of Frank E. Seagrave, his 8-inch Alvan Clark refractor, his observatories and Skyscrapers, Inc. here.

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