Questions tagged [telescope]

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4 votes
1 answer
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How was the first parabolic telescope mirror made, and how was it used, and for what kind of telescope was this work done?

This answer to When was the first true Gregorian telescope built? explains: Newtonian uses one concave and one flat mirror (or just one concave). Gregorian uses two concave mirrors, and Cassegrain ...
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1 vote
0 answers
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Where did Wm. Herschel plan to put their head? Peer over the edge of the famous 40-foot telescope or try to get less off-axis; closer to the center?

From here: click for larger Herschel's 40 foot telescope had a diameter of 48 inches (122 cm) and was f/10. It was not a good mirror (cast in metal) and apparently not used that much. But my ...
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1 vote
0 answers
81 views

When did telescopes become affordable?

There must have been a moment when most people had heard of telescopes, but they were only affordable by rich people or ship's captains. When did they first become affordable by the general public? ...
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4 votes
1 answer
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Is there a record of how Newton built his telescope?

Did Newton write down his process of building a reflector telescope? Even with modern knowledge and technology, building one is no easy task so I'm curious of exactly what Newton did.
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2 votes
1 answer
176 views

Could someone have discovered the moons of Jupiter before Galileo?

As Hans Lipperperhey had made a decent telescope albeit worse telescope before Galileo, source, would he have been able to theoretically view the moons of Jupiter before Galileo if he had looked?
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3 votes
1 answer
86 views

Are there any records of the history for the development of speculum alloy?

I am curious if anyone has seen any records on how this alloy was first developed or perhaps accidentally discovered? One could ask a similar question for any alloy but since this is peculiar in ...
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1 vote
1 answer
170 views

Did Galileo really see Galilean Moons?

I want the answer to incorporate apparent magnitudes of those moons, power of his telescope, light pollution of that time, successful recreation of the scenario of watching Galilean moons using that ...
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2 votes
2 answers
102 views

Where are the mirrors of the historic telescopes today?

Are the great mirrors and lenses of historic telescopes preserved? Those of Herschel and Rosse and many others and back to the 18th and 17th centuries. The wooden structures of those telescopes I can ...
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5 votes
1 answer
478 views

When William Herschel discovered Uranus, who else at the time had a comparable telescope?

William Herschel built a big telescope and observed Uranus in 1781. I'm trying to figure out who else had a comparable telescope at the time, who could verify these observations? Apparently Johan ...
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5 votes
1 answer
488 views

When was the first true Gregorian telescope built?

I know that James Gregory came up with the idea of using a parabolic mirror to eliminate spherical aberration in 1663. The theory behind it had actually been around since classical antiquity I think....
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  • 161
6 votes
1 answer
92 views

What advances allowed Lippershey and Galileo to make working telescopes?

If a working telescope was barely possible at the time of Digges (circa 1570s), what technical advances allowed Lippershey (patent 1608) and especially Galileo (1609 onwards) to create working ...
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17 votes
1 answer
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Did the Digges Telescope actually exist?

There are many claimants for the first telescope. Amongst these are the claims placed at the doors of Bacon and Digges. The Bacon claim is very sketchy, boiling down to one sentence and is easy to ...
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