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WaxRubiks
2017-Jul-31, 07:12 AM
Someone linked to this paper about turning the light from a wall into a reflected image:
https://www.cl.cam.ac.uk/~mgk25/ieee02-optical.pdf

It made me wonder if you had a telescope with a large convex mirror that projected onto a very large spherical dome, whether if you could make the surface sensitive enough to light that you would get a more detailed image, after putting it all though processors maybe?

I'm guessing the limit of this idea maybe the reflection quality may put a limit on the detail you could get..?

Maybe if you made the convex mirror really huge, that would counter that..?22482

selden
2017-Jul-31, 12:19 PM
The article that you link to is about measuring the timing of pulses of light emitted by a CRT screen, not about seeing a reflected image. The reflections it talks about are those pulses of light bouncing off a wall. Those variations in light levels are then used to reconstruct the image that was on the CRT screen. The amount of detail available is determined by the resolution of the image generated on the screen of the original CRT.

The detection method described in the article is almost irrelevant today since CRTs have been replaced by LCD displays which do not generate light pulses in the way that CRTs do. Pixels on a CRT screen are generated one at a time by a single (or a trio of) fluctuating electron beam(s), making it possible to detect each pixel individually by a variety of techniques. "Reflected light" is only one of them.

ShinAce
2017-Jul-31, 12:55 PM
Nope. The resolution will be limited by the size of the tunnel. Might as well have a normal telescope with an aperture the size of the tunnel.

Squink
2017-Aug-01, 02:39 AM
Maksutov telescopes (https://en.wikipedia.org/wiki/Maksutov_telescope)?

ngc3314
2017-Aug-02, 01:19 PM
One astronomical application of a very similar layout was the so-called Oke box, used to increase the sensitivity of intensity measurements in the days (nights) when that was most accurately done with photomultipliers. Since the cathode of the detector tube reflected a significant amount of light, Oke (and maybe others) hit on the idea of surrounding it with a partial sphere with a reflective inner surface (and hole for the light from the telescope to enter), so that much of the light that bounced off on its first encounter would be sent back until it was either detected or absorbed by parts of the structure. IIRC this gave something like a 20% gain in signal.


(Dear autocorrect: how is telecopy more common than telescope?)

Amber Robot
2017-Aug-02, 07:23 PM
One astronomical application of a very similar layout was the so-called Oke box, used to increase the sensitivity of intensity measurements in the days (nights) when that was most accurately done with photomultipliers. Since the cathode of the detector tube reflected a significant amount of light, Oke (and maybe others) hit on the idea of surrounding it with a partial sphere with a reflective inner surface (and hole for the light from the telescope to enter), so that much of the light that bounced off on its first encounter would be sent back until it was either detected or absorbed by parts of the structure. IIRC this gave something like a 20% gain in signal.


(Dear autocorrect: how is telecopy more common than telescope?)

Reminds me of an 'integrating sphere'.