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Biggest Pinhole Camera Ever
universetoday.com ^ | Oct 1, 2004

Posted on 10/01/2004 8:58:17 PM PDT by ckilmer

Biggest Pinhole Camera Ever

Summary - (Oct 1, 2004) A common science experiment for young kids is to build a pinhole camera. Researchers from the University of Colorado at Boulder think NASA should build a gigantic one in space and use it to find planets orbiting other stars. The "New Worlds Imager" would be a football field-sized opaque light shade with a small opening right at the centre to let light through. A detector spacecraft would sit thousands of kilometres back and collect the light that comes through the opening. The shade would block the light from the star and let astronomers detect planets orbiting it. The proposal was one of 12 advanced concepts recently selected for further study by NASA.



For the rest of the article go here.

(Excerpt) Read more at biggest-pinhole-camera-ever.v3.net ...


TOPICS: Culture/Society; Miscellaneous
KEYWORDS: extrasolar; planet; sattelite; space; telescope
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1 posted on 10/01/2004 8:58:19 PM PDT by ckilmer
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To: ckilmer

Suddnely my grade school oalmeal container pin-hole camera seems....so small.


2 posted on 10/01/2004 9:03:45 PM PDT by Covenantor (CBS Counterfeit But Sincere)
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To: ckilmer

Won't work, too much "stray" light between "pinhole" and "detector" spacecraft.


3 posted on 10/01/2004 9:07:01 PM PDT by Shellback Chuck (Olongapo hookers are more truthful than Kerry)
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To: ckilmer

Alignment would be difficult, but it's a wonderful idea.


4 posted on 10/01/2004 9:09:50 PM PDT by hyperpoly8 (Illegitimati Non Carborundum)
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To: Shellback Chuck

if there is too much stray light between the an acre of "paper" in space and a sattelite with a basketball target--then why is there not too much stray light between a pin hole and white paper on earth.


5 posted on 10/01/2004 9:13:14 PM PDT by ckilmer
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To: Shellback Chuck

It would be EXTREMELY inefficient, but relatively cheap.


6 posted on 10/01/2004 9:13:44 PM PDT by Kirkwood (I think, therefore I am Republican!)
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To: ckilmer
Gosh. I had this idea years ago. The thing is you have to match the diffraction limit, which decreases with hole size, with the geometric limit, which increases with hole size. It turns out that for a given pinhole-observer distance, L, the optimum size is approximately the geometric mean of L and lambda, the wavelength of light. lambda ~= 5e-7 meters . So a one-meter pinhole is appropriate for L = 2e6 meters : 2000 kilometers.

I decided it was a stupid idea. Because if your going to use a one-meter aperture, why not just make a telescope?

7 posted on 10/01/2004 9:13:58 PM PDT by dr_lew
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To: ckilmer

The sensor array might be apodized for the position of the "pinhole" to reduce stray light effects.


8 posted on 10/01/2004 9:17:27 PM PDT by Kirkwood (I think, therefore I am Republican!)
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To: ckilmer
Light is collective, hence the amazing example of "time exposures", how far was your pinhole from your paper, here on earth?? not too far I bet. I also bet you were looking at something relatively bright, like the sun during an eclipse. Now take that example into space with a pinhole diaphragm thousands of meters from a detector (the film) and try to shield the detector from all other light sources other than the diaphragm. Too much stray light to interfere with the sensor. Stars, planets, nova's, galaxies, little green men, etc.

At those kind of distances you would still need some kind of lens to focus in on the pinhole, so you would still result in some chromatic aberration
9 posted on 10/01/2004 9:33:56 PM PDT by Shellback Chuck (Olongapo hookers are more truthful than Kerry)
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To: Shellback Chuck

No need for any lens. The photons just pass directly from the pinhole to the sensor array. You could put low-ech light baffles around the individual sensors to cut out on some stray light, but it would still be a problem. The pinhole material itself would have to be anti-reflective.


10 posted on 10/01/2004 9:39:43 PM PDT by Kirkwood (I think, therefore I am Republican!)
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To: Kirkwood

low-ech = low-tech


11 posted on 10/01/2004 9:40:28 PM PDT by Kirkwood (I think, therefore I am Republican!)
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To: Kirkwood

I think dr_lew has this problem down pat.


12 posted on 10/01/2004 9:41:53 PM PDT by Shellback Chuck (Olongapo hookers are more truthful than Kerry)
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To: Kirkwood

Sounds like an enormous focal plane array.


13 posted on 10/01/2004 9:44:43 PM PDT by dr_who_2
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To: Shellback Chuck

Your probably right, but I thought light had to be reflected in order to be "visible" and since space is a vacuum....


14 posted on 10/01/2004 9:47:14 PM PDT by notforhire (It riles them to believe that we perceive the web they weave.)
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To: notforhire

In space there would be billions of direct sources of light all around.


15 posted on 10/01/2004 9:49:35 PM PDT by Shellback Chuck (Olongapo hookers are more truthful than Kerry)
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To: Shellback Chuck

"It was full of stars"......2001


16 posted on 10/01/2004 9:51:07 PM PDT by Shellback Chuck (Olongapo hookers are more truthful than Kerry)
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To: ckilmer; dr_lew
This can be simulated by simply letting the moon, with its crags and fissures, occult the star for you. You would have to be quick, but the technique of shielding one's eyes with his hand should yield some results.
17 posted on 10/01/2004 9:51:17 PM PDT by NicknamedBob (AuthorHouse.com/BookStore), (Hawthorne) A world of only women for 300 years, then, recreationally...)
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To: dr_who_2

It would be similar to a giant ccd array with a giant pinhole positioned in front of it. At least that's how I envision it.
I still prefer a bunch of nuke-power hubble-like telescopes with ion positioning thrusters working together.


18 posted on 10/01/2004 9:54:31 PM PDT by Kirkwood (I think, therefore I am Republican!)
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To: ckilmer
Bump
For Later
19 posted on 10/01/2004 9:56:14 PM PDT by Fiddlstix (This Tagline for sale. (Presented by TagLines R US))
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To: Shellback Chuck

Absolutely! But, I just picture (no pun intended) the images of Armstrong on the moon. There was no atmosphere to reflect the light and it appeared as though he was in complete darkness even though he was standing in direct sunlight.

I don't know. As I said, you’re probably right.


20 posted on 10/01/2004 9:58:42 PM PDT by notforhire (It riles them to believe that we perceive the web they weave.)
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