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Quarterly Review
An Astronomical Undertaking
The Perfect Machine: Building the Palomar Telescope
by Ronald Florence
(Harper Trade, 1994, $14.00)Reviewed by Allan A. Kerin
Ronald Florence's The Perfect Machine is an extremely interesting book about the construction of the Mount Palomar telescope. The project can be viewed as a step in the growth of big science or as the culmination of completely privately funded pure research projects. (The funding was primarily from the Rockefeller Foundation.) The 200-inch telescope was a huge engineering project and the largest and most expensive scientific research program in the world when it began in the late 1920's. Completed in 1949, it was the largest optical telescope in the world and remained so for decades. Although it has been surpassed in size by new innovative telescopes, it remains one of the most important astronomical facilities in the world.
Florence tells a complex story about the technological, financial, and organizational challenges faced during the two-decade-long project. There is also significant discussion of the scientific motivation for building the telescope and of the personalities of many of the scientists, engineers, administrators, opticians, and mechanics who worked on the project.
The heart of the narrative concerns the casting, grinding, and polishing of the great 200-inch mirror. The initial expensive attempts by General Electric to produce fused quartz mirrors were complete failures. The contract was then given to the Corning Glass Works to cast a conventional glass mirror. Corning decided to use Pyrex, which has a much lower coefficient of expansion than ordinary plate glass and hence would be less subject to distortions from changes in temperature. In today's world of personal computers and ubiquitous microchips it is instructive to see that the material needed to make an optically sound 200-inch telescope was already in pie dishes and casseroles in many American kitchens. (The 100-inch Mount Wilson telescope mirror had been cast from plate glass.) Corning and Dr. George McCauley, the Corning researcher who directed the Palomar mirror project, are deservedly described as heroes.
Amid a great deal of publicity the completed mirror disk was shipped in 1936 by rail from Corning, NY to Pasadena, CA on a special four-car train that was given the highest priority throughout the cross-country trip. Crowds lined the track in cities and towns along the way. Eleven years later (including a four-year pause during World War II), in October 1947 the grinding and polishing of the mirror was finally complete. During this time the telescope tube and mounting, auxiliary mirrors, machinery, building, and dome were being built. Many of the mechanical components of the huge telescope had to be built to unprecedented degrees of precision to ensure proper alignment of the mirrors and accurate tracking of objects.
This book describes the talent and diligence of those who planned and built the telescope. It also notes some of their occasionally humorous peculiarities. For example, the great astronomer Edwin Hubble was born and raised in Missouri, studied for a few years in Britain, and after that spoke with an "acquired English accent" for the remainder of his life. Byron Hill, the first superintendent of the observatory, expelled an astronomer from the facility for wearing shorts to lunch. When the telescope began operation, women were not allowed to be staff members or observers. A great deal of progress has been made in the 52 years since the telescope was completed!
I highly recommend this informative and entertaining book. The book's one shortcoming is that the descriptions of the structure of the telescope are woven into the narrative and are sometimes hard to follow. An introduction or appendix containing a clear description of the design would have been helpful.