How amateur telescope makers defended America

John Mellish, a young farmer from Wisconsin with only a grade-school education, had a passion for observing the stars. At the dawn of the 20th Century, however, a three-inch refractor from Alvan Clark & Sons was priced at $175, which was unaffordable for Mellish. Despite this, his skills and ingenuity led him to build a six-inch Newtonian telescope for just $15, thanks to an article by astronomer George Ritchey in Scientific American. Mellish later used this telescope to discover two comets. After sharing his story in a letter to Popular Mechanics, Mellish received over 300 responses, sparking an unexpected career in making and selling telescopes.

James Baker’s 1941 optical shop located in the basement of the Harvard College Observatory

Photo credit: John G. Wolbach Library/National Archives in Boston

Mellish’s achievements inspired Russell Porter, an energetic and talented individual, to establish the hobby of amateur telescope making in the US. Born in Springfield, Vermont, in 1871, Porter had a diverse background in art, engineering, and architecture and had participated in eight Arctic expeditions from 1893 to 1906. While recuperating from these adventures, Porter discovered Mellish’s letter in Popular Mechanics and developed an interest in optics and astronomy.

By 1912, Porter was proficient in making telescope mirrors, and by 1920, he was skilled enough to teach telescope-making to a group of 16 people from a local machine shop, including the only woman there, Gladys M. Piper. This group, minus Piper, who relocated in 1921, became the core of the Springfield Telescope Makers, the nation's first amateur telescope club, which still hosts the annual Stellafane convention. In 1921, Porter published "The Poor Man’s Telescope" in the November issue of Popular Astronomy.

Porter recognized the potential for amateur telescope making in the 1920s due to the availability of optical glass and equipment and widespread machining skills. However, his article initially received little attention. The story might have ended there if not for Albert Graham Ingalls, a writer for Scientific American, who discovered Porter’s article in the New York Public Library in 1923. Ingalls contacted Porter, and with Porter’s guidance, built his telescope.

In 1942, James Baker's optical shop, initially meant to house the New England Depository Library, was repurposed for war efforts

Photo credit: John G. Wolbach Library/National Archives in Boston

In the November 1925 issue of Scientific American, Ingalls made telescope-making appear accessible, stating that one needed only patience, basic tools, and household items. This led to a surge of interest, resulting in a three-part series in early 1926 and a longer book version, which saw continued use for decades. By the end of 1926, over 1,500 readers were building telescopes.

Amateur astronomy clubs began to form in cities like New York, Chicago, Denver, and Los Angeles. By May 1928, the number of telescope makers had doubled, and Ingalls’ column in Scientific American became the hub for this burgeoning community.

During the Great Depression, the hobby continued to grow as it was an inexpensive project for people with time but little money. Ingalls’ persistent promotion in Scientific American fostered an inclusive environment where anyone could construct a high-quality telescope with simple tools.

As tensions rose in Europe, the US optics industry faced challenges in matching German technology. The need for high-quality image inverters for military optics became critical. Ingalls and his group of amateur telescope makers, known as the “Roof Prism Gang,” played a vital role in addressing this need. By 1940, Fred B. Ferson was already producing roof prisms in his garage, demonstrating that amateurs could contribute to complex optical production.

With war looming, Porter recruited members of the Los Angeles Astronomical Society and the Milwaukee Astronomical Society to join the effort. Ingalls, Ferson, and Porter, along with Herschel Ice from the US Army Frankford Arsenal, developed a standard manufacturing procedure for roof prisms. Volunteers produced sample prisms for testing, and those who passed went on to produce larger batches.

The Roof Prism Gang eventually included 80 amateurs who produced about 10 percent of the military’s required prisms, with Fred Ferson alone manufacturing 11,600 of the 28,420 prisms produced. Their yield surpassed 90 percent, a success even professional opticians could not match.

During the war, amateur astronomers also helped train military personnel in celestial navigation and other skills. James Baker, a Harvard astronomer and telescope maker, played a crucial role in developing advanced reconnaissance cameras for the Army Air Corps, leading to significant advancements in aerial photography.

The contributions of these amateur telescope makers, from John Mellish to James Baker, not only fostered a vibrant hobby but also played a critical role in advancing optical technology during WWII and the Cold War. This remarkable legacy began with a Wisconsin farmer’s simple desire to observe the stars more closely.