
Nipkow disk - Hooke
https://en.wikipedia.org/wiki/Nipkow_disk
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vesinisa
Here is an excellent in-depth explanation of the concept from one of my
favorite educational YouTube channels - Technology Connections:
[https://youtu.be/v5OANXk-6-w](https://youtu.be/v5OANXk-6-w)

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Zenst
I just watched that and have to agree, an excellent in-depth explanation it
was indeed, with a lovely demonstration.

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auggierose
A descendant of this guy is hard at work in theorem proving:
[http://www21.in.tum.de/~nipkow/](http://www21.in.tum.de/~nipkow/)

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YorkshireSeason
Is this a joke or is Tobias a (great) grandson of Paul Gottlieb's?

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auggierose
Not a joke. I asked him about that (quite) a few years ago, and he indeed is
:-)

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gdk
William Osman tried to build a mechanical display around these:
[https://www.youtube.com/watch?v=R96TtG5FCTU](https://www.youtube.com/watch?v=R96TtG5FCTU)

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felipemnoa
He seems to really be overcomplicating its construction with all those fancy
21st century electronics when in reality you can build it with early 20th
century materials.

I wonder if a camera obscura would be enough to create the focused image
instead of having to bother with lenses.

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Sharlin
Probably, but that would require even more light.

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inflatableDodo
Thanks for this, I have been trying to remember the term 'confocal microscopy'
for a while.
[https://en.wikipedia.org/wiki/Confocal_microscopy](https://en.wikipedia.org/wiki/Confocal_microscopy)

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felipemnoa
This is a really good short educational video about the invention of
television:

[https://www.youtube.com/watch?v=MyHAev_qJNU](https://www.youtube.com/watch?v=MyHAev_qJNU)

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JoeAltmaier
This is very similar to the old fax machines, that had a needle over a
rotating text on a wax cylinder and reproduced the needle up-down on the other
end with a pen. Predated telegraph etc.

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sp332
I don't understand why you have to approximate straight scanlines by using a
fraction of a really large disk. What's the disadvantage in using a smaller
disk and letting the scanlines be curved?

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Koshkin
With the large disk, the difference between the (linear) velocities of
different holes is smaller.

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oakwhiz
Could it be possible to use this mechanism to create a type of X-ray or gamma
ray camera? Perhaps using a lead disc.

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LeoPanthera
The spelling of disk, with a K, intrigues me, since I was under the impression
that disk-with-a-K was short for "diskette", meaning a circular spinning
object protected inside an outer casing.

Circular flat objects are spelled disc, with a C.

Hence floppy disk, hard disk, but compact disc.

(MiniDisc is the only exception to this rule that I can think of, probably
because it is a trade mark.)

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Sharlin
Seems Wikipedia has a dedicated article on the subject!

[https://en.wikipedia.org/wiki/Spelling_of_disc](https://en.wikipedia.org/wiki/Spelling_of_disc)

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dmix
Relevant bit:

> in the case of flat, rotational data storage media the convention is that
> the spelling disk is used for magnetic storage (e.g. hard disks) while disc
> is used for optical storage (e.g. compact discs, better known as CDs). When
> there is no clear convention, the spelling disk is more popular in American
> English, while the spelling disc is more popular in British English.

