On an excursion

If you wish to read the latest words of wisdom, this time on the conception and invention of the reflecting telescope, then you will have to take an excursion to AEON magazine, where you can peruse:

How many great minds does it take to invent a telescope?

Isaac Newton’s reflecting telescope of 1671. Photo ©The Royal Society, London


Filed under History of Astronomy, History of Optics, History of Technology, Newton

2 responses to “On an excursion

  1. “All true reflectors have at least two mirrors: a primary mirror that forms the image, and a secondary mirror that projects the image out of the body of the telescope.”

    Not quite true. Sir William Herschel tilted the primary mirror of his 48″ reflector, to bring the paraboloid focus to the edge of the telescope tube (called the “Herschellian view”), while the 3m Lick telescope and 5m Palomar telescope both had prime focus observer cages.

    But then, even Homer nods.

    • I’m actually well aware of the fact that both Herschel’s 20 foot and 40 foot reflectors didn’t have a secondary mirror and that the image was viewed, using a telescope eyepiece, by peering down the tube from the front. In fact although Herschel built Newtons, in an age when most others were building Gregorians, his two very large telescopes are technically Zucchis. Unfortunately a fairly strict word count limit prevented the inclusion of such subtleties

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