Celestron, one of the world’s best-known names in telescopes, is marking 2010 as its 50th anniversary year. While other telescope companies have reached this milestone, Celestron stands out for its current success (com pany president and CEO, Joseph Lupica, reports that 2009 was Celestron’s second best year ever) and a continued commitment to its founding vision of serving the astronomy community, especially “serious” amateurs. Indeed, the 5-, 8-, and 14-inch Schmidt-Cassegrain telescopes that set the course for Celestron’s future in the early 1970s are still flagship instruments in the product line. But they were not the scopes that launched the brand. For those, we need to step back another decade.
Thomas J. Johnson, Celestron’s founder and the genius behind the modern Schmidt-Cassegrain telescope, was in his early 30s when he used his World War II experience as a radar technician and post-war employment in the electronics industry to establish Valor Electronics in 1955. Based in Gardena, California, Valor made a variety of components for military and industrial customers, and by the early ’60s it had expanded to roughly 100 employees.
As Valor was growing, so too was Johnson’s interest in amateur astronomy. First purchasing 4- and later 10-inch Newtonian reflectors from Cave Optical – one of the preeminent brands in North America during the ’50s – Johnson then headed down a path followed by many amateurs of the day and turned to the hobby of telescope making. In 1960 he established the Astro-Optical division of Valor. His first scope was an 8-inch f/4 “rich-field” Newtonian, and it was soon followed by a 12-inch Cassegrain.
His next project, however, was a highly unconventional 183A-inch Cassegrain made to be transportable. To reduce the weight of the 3-inch-thick primary mirror, Johnson had a ribbed pattern sandblasted into the back of the glass blank. Six months and about $1,000 later, he had a fork-mounted scope that could be disassembled and packed into a car in about 15 minutes. On July 28, 1962, he hauled the scope to the parking area atop Mount Pinos for its public debut at one of the Los Angeles Astronomical Society’s star parties. It made a big impression among the group’s advanced amateurs who examined it in detail. The telescope was so noteworthy that it became the cover story of this magazine’s March 1963 issue.
But it was another S&T article that proved especially influential in Celestron’s history. As Johnson was nearing the completion of his 183/4-inch scope, Donald Willey published a seminal analysis of Cassegrain telescopes in the April 1962 issue. Johnson was intrigued by the excellent off-axis optical performance of the Schmidt-Cassegrain design. Based on his experience building the 18/-inch scope (some of the work involved other Valor employees) and a plan to use optics made to order by Perkin-Elmer Corporation, Johnson took the bold step of advertising a 20-inch multipurpose Schmidt-Cassegrain telescope called the Celestronic 20 in S&T’s January 1964 issue.
The Astro-Optical Division name quickly morphed to Celestron Pacific, a division of Valor. By December Valor was dropped, and Celestron’s ad introduced pictures of 4-, 6-, 10-, and 22-inch Schmidt-Cassegrain telescopes as well as mention of a 36-inch. A 16-inch entered the product line in early 1967. But most of Celestron’s sales were for the 10-inch, which cost about $2,000 when outfitted with a few basic accessories.
Despite his initial arrangement with Perkin-Elmer, Johnson experimented with making his own Schmidt- Cassegrain optics. From the outset, he and his colleagues were able to produce them at a pace needed to meet orders. A breakthrough came early on when Johnson blended known technologies with his own experience and techniques to create a method for effectively mass producing the telescopes’ optically complex corrector plates. For this and other contributions to optics, Johnson was later awarded the Optical Society of America’s prestigious David Richardson Medal, one of only a few non-Ph.D. optical engineers to ever receive the honor.