12

It all depends on your definition of a telescope. Digges absolutely built some sort of device that was capable of magnifying objects. It seems that is agreed upon. But the divide is really about whether or not this was a telescope. Some historians shrug it off as little more than a powerful spyglass; others herald it as the first telescope. There are ...


7

There can be no doubt that he has seen them, for the simple reason that he determined their periods and configuration correctly, and published them. Therefore the other things (magnification of his telescope, light pollution etc.) are irrelevant for the answer. You can easily see them yourself using an 8x binocular.


4

(Partial answer - and a bit long winded) Regarding comparable telescopes - source : The Herschel Objects and How to Observe Them, by James Mullaney. Herschel's telescopes far surpassed in both quality and size any other telescope in the world at the time. After comparative trials at a number of observatories in England including Greenwich, he stated ...


2

There is a confusion in your question. ALL reflecting telescopes ideally should have parabolic mirrors. The problem is that a parabolic mirror is difficult to make. So they were made with spherical or approximately parabolic mirrors. All this has nothing to do with the difference between Newtonian, Gregorian and Cassegrain telescopes. The distinction ...


2

One of the most important mirrors historically is that of Sir Isaac Newton's telescope shown below. In the Periodic Video Amazing piece of metal (speculum), Professor Martyn Poliakoff (CBE, CChem, FRS, FRSC, FIChemE) describes the telescope, notes about building the telescope, and what is believed to be the speculum mirror used in the telescope, at the Royal ...


1

Given that it's reasonably easy to see the 4 major moons with a 6 to 8- power binoculars, (you can find hundreds of discussions of planet-gazing with binocs online) it is quite reasonable to suppose that a patient, skilled observer with a 3 or 4 X telescope could have observed these moons. Keep in mind that Lipperperhey, or users of his 'scope, would have ...


1

The only descriptions I have seen seem to show by implication how experimental (and perhaps accidental) the subject was. Newton was a long way from being the first to investigate speculum metal, but for the following reasons his descriptions can form a useful reference-point: (a) Some of the difficulties of accounting for early developments in 'chymistry' ...


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