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#11
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there are severl ways to do this
1) a hot plasma is transparent, and magnetically confinable/ shapeable - google Fresnel Oscillations 2) water is a polar molecule - use a static field to shape a water lens 3) if you look at the eigenmodes of oscillation of a 'drum' you may be able to produce a fresnel zone plate in some kind of optical medium via magneto acoustics 4) with the advent of new electro optice materials, it may be possible to induce optical holographic effects in a material couple this with high speed detectors and image processing and it may be possible to have super resolved holographic imaging soon if not now "phoenix" wrote in message oups.com... Theoretically. Is it possible to construct a telescope using holographic lens such that you flick a switch and the lens just formed at the front. I like the idea of a very lightweight 0 wave error 6" refractor that I can carry at my back when hiking and just putting it on the equally lightweight image stabilizer mount when the sky has a great view. In 4000 A.D. Can the above occur.. theoretically?? phoenix |
#12
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phoenix wrote:
Strong mass can bend light. Maybe putting heavy neutron star matter at the periphery of the tube?? But then it's no longer lightweight unless 4000 A.D. technology has developed antigravity so you can take it along with you as well as higgs field suppressor to prevent the heavy neutron star mass from being formed while being carried. If you have anti-gravity at your disposal, you won't need neutron star matter. The anti-gravity emitter can bend (unbend?) light all by itself. That's all you need, an anti-gravity lens. It would work like the Einstein Cross gravitational lens, only smaller and the other way around. http://www.astr.ua.edu/keel/agn/qso2237.html |
#13
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phoenix wrote:
Theoretically. Is it possible to construct a telescope using holographic lens such that you flick a switch and the lens just formed at the front. I like the idea of a very lightweight 0 wave error 6" refractor that I can carry at my back when hiking and just putting it on the equally lightweight image stabilizer mount when the sky has a great view. In 4000 A.D. Can the above occur.. theoretically?? Theoretically anything that is not prevented by the laws of physics is possible. However, many practical limitations do get in the way. Most notably that a hologram uses diffraction and so will suffer from horrific chromatic abberations unless it is used for monochromatic light. Fresnel zone plates can already be used to form crude images by diffraction. If you can live with the image quality. e.g They have their own following in the pinhole camera community. You could argue with some justification that modern aperture synthesis radio telescopes are in effect holographic instruments since they combine the phase compensated coherent signals sampled at various locations (and times) to compute what would have been seen by a real filled aperture. The phase compensation issues are so difficult that I doubt if anyone will ever make a portable optical aperture synthesis scope... Regards, Martin Brown |
#14
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"Is it possible to construct a telescope using
holographic lens such that you flick a switch and the lens just formed at the front." Not quite, but about 15 years ago I read an article in Advanced Optics that whowed if you took a 1 wave reflector, a laser, and a holographic plate, that you could print the wavefront error on that plate. Then later after the plate was developed, you could use the plate to convert the scope from a 1 wave monster into a 1/3 wave--almost tollerable--scope. However, the colimation tollerances with respectof plate to optical axis were "really stiff". Mitch |
#15
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A while ago I saw a product called "digilens"
that was 3 ? diffractive lenses in one lens holder. You could switch between them with an address line. The optical properties of this optic were programmed at the factory. The one I saw (photo) had 2 positive and one negitive lenses of different focal lengths IIRC Dan wrote: "Is it possible to construct a telescope using holographic lens such that you flick a switch and the lens just formed at the front." Not quite, but about 15 years ago I read an article in Advanced Optics that whowed if you took a 1 wave reflector, a laser, and a holographic plate, that you could print the wavefront error on that plate. Then later after the plate was developed, you could use the plate to convert the scope from a 1 wave monster into a 1/3 wave--almost tollerable--scope. However, the colimation tollerances with respectof plate to optical axis were "really stiff". Mitch |
#16
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On 25 Apr 2005 03:14:12 -0700, "phoenix" wrote:
Theoretically. Is it possible to construct a telescope using holographic lens such that you flick a switch and the lens just formed at the front. I like the idea of a very lightweight 0 wave error 6" refractor that I can carry at my back when hiking and just putting it on the equally lightweight image stabilizer mount when the sky has a great view. In 4000 A.D. Can the above occur.. theoretically?? I can't see holographic equipment being very portable at first. Even when it is, I'm sure it will be easier to simply GO within a few dozen light years of the Great Orion Nebula and get a real view or take up a nice spot on Ganymede on the sub-Jovian side at night and watch the GRS spin or use 10x50 binoculars to watch the latest Pele eruption on Io. Guess we'll still need telescopes to see galaxies though. :-) Later generation light intensifiers and liquid mirrors are likelier to make amateur astronomy more enjoyable before the advent or portable or amateur holography equipment. -Drew |
#17
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Drew wrote: On 25 Apr 2005 03:14:12 -0700, "phoenix" wrote: Theoretically. Is it possible to construct a telescope using holographic lens such that you flick a switch and the lens just formed at the front. I like the idea of a very lightweight 0 wave error 6" refractor that I can carry at my back when hiking and just putting it on the equally lightweight image stabilizer mount when the sky has a great view. In 4000 A.D. Can the above occur.. theoretically?? I can't see holographic equipment being very portable at first. Even when it is, I'm sure it will be easier to simply GO within a few dozen light years of the Great Orion Nebula and get a real view or take up a nice spot on Ganymede on the sub-Jovian side at night and watch the GRS spin or use 10x50 binoculars to watch the latest Pele eruption on Io. Guess we'll still need telescopes to see galaxies though. :-) Later generation light intensifiers and liquid mirrors are likelier to make amateur astronomy more enjoyable before the advent or portable or amateur holography equipment. -Drew Maybe a 4" holographic lens is a bad idea. Perhaps it would be far more useful to have much bigger aperture like 10" refractor. As you know. Big aperture refractor costs like crazy. Maybe they can invent something that can collect the photons in a say 20 inches area and focus the beam to the focal point that doesn't even use glass but other methods such some kind of wave guide to guide all the waves into a point at the focal plane. Got any idea how or what that can do it roughly even on a theoretical basis first awaiting technology advances thousands of years far into the future. Well. It's not bad to start thinking of it now as we may be able to build a rough device that can do it. P |
#18
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William McHale wrote: RichA wrote: On 25 Apr 2005 03:14:12 -0700, "phoenix" wrote: Theoretically. Is it possible to construct a telescope using holographic lens such that you flick a switch and the lens just formed at the front. I like the idea of a very lightweight 0 wave error 6" refractor that I can carry at my back when hiking and just putting it on the equally lightweight image stabilizer mount when the sky has a great view. In 4000 A.D. Can the above occur.. theoretically?? phoenix No. I don't care what they could do on the Enterprise holodeck, it was all nonsense. But, maybe a ring of controllable and tiny black holes around the periphery of the objective opening could be used to "bend light" to achieve the results you're looking for. Kind of like how an electron microscope uses magnets instead of lenses to manipulate electrons. You could also put a single slightly larger black hole in the center of the objective opening. Of course this would not make refractor people happy since you would now have an obstructed system. not to mention instant vanishing of the observer! Oooooops. |
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