The Telescope

Due to budgetary constraints regarding the submittal of the observatory as a federal Public Works Administration (PWA) project, Clarence T. Jones and the BAS vowed to procure a telescope themselves to ensure approval. As a last resort, Mr. Jones even committed to donating his own 12-inch reflector telescope as a backup. However, that ended up not being necessary.

Mr. Jones initially enquired about the costs of purchasing a suitable telescope for the new observatory. After a considerable amount of research, he found the best proposal available was around $12,000 (~$270,000 today), which was significantly beyond the financial means of any of those involved.

As early as the Fall of 1934, however, Mr. Jones was fortunately already in collaboration with Mr. Marion C. Wall of the Chattanooga Engineers Association to produce drawings for the desired 20.5-inch Cassegrain telescope. Once the path for a separate telescope was decided, he submitted those drawings to the Eureka Foundry of Chattanooga for assessment. The company generously stated they would donate their labor to the project and that only the cost of the castings necessary for the fork mounting and base would be charged ($700; ~$16,000 today).

Clarence T. Jones and Bruce Jones standing on the 200” Palomar test blank (Image Credit: unknown photographer)

In addition, Clarence T. Jones and his sons Arthur and Bruce had already designed and built the motor-driven grinding lap required for making the mirrors on their own. Based on previously published records by F. M. Cordell, Sr. (a former BAS archivist), the Jones family also bought low expansion Pyrex optical glass from the Corning Glass Works company located in Corning, New York for the primary and secondary mirrors at a personal cost of about $1,000 (~$23,000 today). Rumor has it, the primary mirror blank may be one of the original “test” pourings for the historic 200-inch mirror at the Palomar Observatory. A third small glass blank was also ordered just in case they decided to make the telescope a Newtonian style instead. However, as Mr. Jones once stated, “We are going to do it, Cassegrain telescopes have been built, we can build one”.

Grinding of the 20.5” mirror in the basement of the observatory (Arthur Jones and Clarence T. Jones; unknown photographer 1937)

Thanks to the generosity of the Eureka Foundry and Jones family, and the ability to build everything locally, the final tabulated cost of constructing the desired 20.5-inch Cassegrain telescope was reduced to $1,700 (~$40,000 today), which the city agreed to cover. In the June 19, 1936 article of The Chattanooga Times, the Commissioner of Education (Mr. T. H. McMillan) announced that “splendid co-operation” from manufacturers submitting bids (on the remaining necessary budget) will make it possible for a $10,000 (~$230,000 today) telescope to be installed in the new astronomical observatory. With plans, manufacturing, and funding finally in place, construction of the largest amateur-built telescope in the United States and of its kind in the Southeast at that time began in early 1937.

Cutting the 4-inch diameter hole in the 20.5-inch mirror in the basement of the observatory (Arthur Jones and William Armstrong; unknown photographer 1937)

Casting by the Eureka Foundry, patterns by the Strickland Pattern Works, and machinery by the Smith Elevator and Manufacturing Company was of course under the direct supervision of Clarence T. Jones. However, the mirrors were made in the basement workshop of the recently completed observatory and were primarily a Jones family affair, with Arthur Jones taking on a significant portion of the work. Arthur even used his experience of making the mirrors to write his 1939 Bachelor of Science in Mechanical Engineering thesis (“Processes Envolved in Producing a Twenty Inch Telescope Mirror”) while at the University of Tennessee (UT) due to the innovative nature of the whole process. A moving silent picture, which is unfortunately likely lost to history, was also made by Clarence T. Jones showing the grinding and polishing of the primary mirror.

Installation of the Telescope (unknown photographer 1937)

With the telescope finally finished and mounted, the fully completed observatory was open to the public for the first time on July 4, 1937. The BAS helped as guides but also provided programs during the initial 10-day open house. Prominent civic and business leaders were invited for a private function on the final day. Daily articles in the Chattanooga Daily Times, some with pictures, were written about the big event. The culminating article on July 15, 1937 stated that “The Barnard Astronomical Society had its biggest party last night, when it entertained more than 500 persons”.

Chattanooga Daily Times article highlighting observatory open house (July 15, 1937)

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“The study of astronomy has taught me to look at the world in a different way and has given me a deeper appreciation for the beauty and wonder of the universe” - Caroline Herschel

Image Credit: BAS Member Carrie Walden