May 31, 2020

Review: Seeing & Believing by Richard Panek

Much has been said over the years about how the invention of the telescope has changed the science of astronomy, but how has it changed us and our view of our place in the scheme of things? Enter Seeing & Believing: How the Telescope Opened Our Eyes and Minds to the Heavens by Richard Panek. I discovered this amazing little book in our local library from a reader tip, and found it a thoroughly interesting and engaging read.

Seeing traces our understanding from the construction of simple convex lenses to their application and use. The author notes that the means to construct a telescope lay about in glassmaker’s workshops for centuries, waiting for someone to make a connection. Galileo was not the first to invent the telescope, nor was he the first to turn it skyward; but he was, however, the first to record and analyze what he saw. Many a discovery was ignored simply for the fact that no one thought to look for them; the heavens were thought to be immutable, unchanging, and separate from the Earth. Like the books The Telescope and the Transits of Venus reviewed earlier this year, Seeing illustrates the evolution of our understanding by linking snapshots of key events. It amazes me the focal lengths that some of those early refractors grew to, (telescopes were measured in tube lengths instead of aperture size in the early days) some as long as 150 feet! It must have been quite a challenge to aim such ungainly beasts, and tougher still to gain any useful observations from them. William Herschel himself is said to have preferred the use of his 20 footer as his primary workhorse, saving the huge 40 foot scope for only the toughest of objects.

Seeing traces the evolution of classical telescopes from the initial Galilean and Keplerian telescopes up through the forking of reflector and refractor lines right up through to the modern day. Perhaps it could be said that the classical age of telescopes culminated with two instruments; the 72” diameter Leviathan of Parsonstown and the 40” Yerkes refractor. Both represented the limits of what was possible with 19th century technology and the hunger for ever more light gathering power. The Leviathan was the largest speculum metal mirror ever constructed, and allowed the Earl of Rosse to discover the spiral nature of galaxies, starting with M51. The Yerkes refractor was (and still is) the largest refractor ever constructed, and the first in a building spree of American telescopes conceived by George Ellery Hale.

Larger works would have to await new innovations, such as silvered mirrors, site selection and computer control. A fundamental shift in thinking began in the early 20th century as the application of photography and spectroscopy came to the fore. Here at last was a way the astronomers could reach out and “taste” the heavens. A realization that whole new realms of exploration lay beyond the optical was also the result of several surreptitious discoveries. Again, no one thought to explore the universe beyond the visual, simply because it never occurred to anyone that something should be there!

So, how has the telescope and astronomy changed us? If nothing else, Seeing illustrates that it has been a long and difficult shift from posing how the universe should be to accepting how it truly is. Perhaps individuals like Galileo and his ilk are noteworthy simply because they recorded objects such as the Moon or Venus as faithfully as their primitive instruments allowed them, without embellishment or garnish. We’ve often wondered why no one tried their hand at faithfully sketching the visible surface of the Moon in pre-telescopic times; after all, a full Moon is larger and brighter in apparent size (Mars email hoax not withstanding) than Mars viewed even at a good opposition through the eyepiece. Was it just the opinion that the Moon was perfect and hence not worth depicting? If it wasn’t tidally locked, but instead rotated as seen from the Earth, would that have changed our perception of things?

Do hunt down Seeing and Believing for a fascinating study of how our outlook and perception has changed over time as our technology has evolved. It stuns me still that I own an 8” Schmidt-Cassegrain that in many ways is a superior instrument to those used by Hershel  or Cassini… just what other discoveries are buried in the real or cyber skies, unappreciated because no one has yet thought to search for them?


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