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:
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:
Filed under History of Astronomy, History of Optics, History of Technology, Newton
If your philosophy of [scientific] history claims that the sequence should have been A→B→C, and it is C→A→B, then your philosophy of history is wrong. You have to take the data of history seriously.
John S. Wilkins 30th August 2009
Culture is part of the unholy trinity—culture, chaos, and cock-up—which roam through our versions of history, substituting for traditional theories of causation. – Filipe Fernández–Armesto “Pathfinders: A Global History of Exploration”
thonyc on Renaissance Science – XLI… | |
ANR on Renaissance Science – XLI… | |
Michael Weiss on Renaissance Science – XLI… | |
thonyc on Renaissance Science – XLI… | |
Jon Awbrey on Renaissance Science – XLI… |
“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