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Main
Date: 24 Jun 2007 20:05:00
From: Sam Wormley
Subject: Plans for a Liquid Lunar Telescope
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Plans for a Liquid Lunar Telescope
http://www.universetoday.com/2007/06/21/plans-for-a-liquid-lunar-telescope/
NASA-funded researchers are working on a clever technology that could
deploy a gigantic telescope made from rotating liquid\u2026 on the
Moon! It sounds like science fiction, but they've gotten smaller
prototypes to work, and the technology should work even better on the
lower lunar gravity.
Here's how it works. Astronauts would deliver the observatory (all
folded up) to the Moon during one of their upcoming "return to the
Moon" missions. It would unfold into the shape of a telescope mirror
made of mesh. The astronauts then pour a reflective liquid onto the
mesh. The mesh rotates coating the entire surface in the liquid.
Don't worry about the liquid dripping through the mesh, it actually
gets held in place by surface tension.
As telescopes go, this would be a whopper. The current plans call for
a 20-metre mirror, but it could theoretically get as big as
100-metres across. This would provide 1000 times the observing power
as the James Webb Space Telescope, which still won't launch for a few
more years. That gives it the power to look right back to the very
edge of the observable Universe, and see the first generations of
stars forming.
Now there's a reason to send humans back to the Moon.
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Date: 28 Jun 2007 16:15:32
From: Guy Macon
Subject: Re: Plans for a Liquid Lunar Telescope
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Helpful person wrote:
>Maybe not through direct friction but a magnetic bearing does not
>isolate noise.
It does isolate some noise/vibration, but not all.
A magnetic bearing does a pretty good job with high-frequency
vibration, a very poor job at resonance, and has virually no
effect at low frequencies. Viscous damping helps the resonance
problem at the cost of smearing the effect over a wider range
of frequencies.
A magnetic baering with active isolation, on the other hand,
is as close to perfect as the actuators and sensors allow,
which in real life is really quite good.
--
Guy Macon
<http://www.guymacon.com/ >
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Date: 26 Jun 2007 18:40:42
From: TBerk
Subject: Re: Plans for a Liquid Lunar Telescope
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Perhaps we could form large rotating telescopes and place them in
orbit around the Earth/Sun.
Then beam back a vid signal to base camp.
TBerk
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Date: 27 Jun 2007 21:52:59
From: lal_truckee
Subject: Re: Plans for a Liquid Lunar Telescope
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TBerk wrote:
> Perhaps we could form large rotating telescopes and place them in
> orbit around the Earth/Sun.
It's gravity that pulls the rotating fluid into a paraboloid. You lose
the whole point is you park it in microgravity.
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Date: 26 Jun 2007 16:37:39
From: Jim Klein
Subject: Re: Plans for a Liquid Lunar Telescope
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Every optical design has some intrinsic residual aberration for which
there are insufficient degrees of design freedom to completely remove.
As you scale up the telescope size, you scale up the residual
aberrations while the 2.44*lambda/D angular diffraction limit
decreases.
This eventually places a practical engineering/fiscal limit on the
size of extended field of view telescopes.
I'm not saying it is met at 100 meters but eventually there becomes
insuffient human will, engineering skill or funding $ to pull the
whole thing off.
Jim Klein
James E. Klein
jameseklein@earthlink.net
Engineering Calculations
http://www.ecalculations.com
ecalculations@ecalculations.com
Engineering Calculations is the home of
the KDP-2 Optical Design Program
for Windows.
1-818-507-5706 (Voice and Fax)
1-818-823-4121
"KDP2, not quite easy enough for a Caveman to use" :-)
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Date: 26 Jun 2007 19:23:02
From: Ioannis
Subject: Re: Plans for a Liquid Lunar Telescope
|
Sam Wormley wrote:
> Plans for a Liquid Lunar Telescope
>
> http://www.universetoday.com/2007/06/21/plans-for-a-liquid-lunar-telescope/
>
> NASA-funded researchers are working on a clever technology that
> could deploy a gigantic telescope made from rotating liquid\u2026
> on the Moon! It sounds like science fiction, but they've gotten
> smaller prototypes to work, and the technology should work even
> better on the lower lunar gravity.
[snip for brevity]
> Now there's a reason to send humans back to the Moon.
A related question: Does anyone know which (polished) metal has the highest
reflectance in the visible range 380-700nm?
I know Al, Ag and perhaps Hg are good candidates, but I want to know which are
the best contenders.
Many thanks,
--
I.N. Galidakis --- http://ioannis.virtualcomposer2000.com/
----------------------------------------------------------
"There's ALWAYS a mistake somewhere"
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Date: 26 Jun 2007 16:39:45
From: Sam Wormley
Subject: Re: Plans for a Liquid Lunar Telescope
|
Ioannis wrote:
> Sam Wormley wrote:
>> Plans for a Liquid Lunar Telescope
>>
>> http://www.universetoday.com/2007/06/21/plans-for-a-liquid-lunar-telescope/
>>
>> NASA-funded researchers are working on a clever technology that
>> could deploy a gigantic telescope made from rotating liquid\u2026
>> on the Moon! It sounds like science fiction, but they've gotten
>> smaller prototypes to work, and the technology should work even
>> better on the lower lunar gravity.
> [snip for brevity]
>
>> Now there's a reason to send humans back to the Moon.
>
> A related question: Does anyone know which (polished) metal has the highest
> reflectance in the visible range 380-700nm?
>
> I know Al, Ag and perhaps Hg are good candidates, but I want to know which are
> the best contenders.
>
> Many thanks,
See: http://www.llnl.gov/tid/lof/documents/pdf/244132.pdf
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Date: 26 Jun 2007 22:28:23
From: Sjouke Burry
Subject: Re: Plans for a Liquid Lunar Telescope
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Sam Wormley wrote:
> Ioannis wrote:
>> Sam Wormley wrote:
>>> Plans for a Liquid Lunar Telescope
>>>
>>> http://www.universetoday.com/2007/06/21/plans-for-a-liquid-lunar-telescope/
>>>
>>>
>>> NASA-funded researchers are working on a clever technology that
>>> could deploy a gigantic telescope made from rotating liquid\u2026
>>> on the Moon! It sounds like science fiction, but they've gotten
>>> smaller prototypes to work, and the technology should work even
>>> better on the lower lunar gravity.
>> [snip for brevity]
>>
>>> Now there's a reason to send humans back to the Moon.
>>
>> A related question: Does anyone know which (polished) metal has the
>> highest
>> reflectance in the visible range 380-700nm?
>>
>> I know Al, Ag and perhaps Hg are good candidates, but I want to know
>> which are
>> the best contenders.
>>
>> Many thanks,
>
> See: http://www.llnl.gov/tid/lof/documents/pdf/244132.pdf
>
No response from www.llnl.gov
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Date: 26 Jun 2007 20:09:56
From: Ioannis
Subject: Re: Plans for a Liquid Lunar Telescope
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Sam Wormley wrote:
> Ioannis wrote:
[snip]
>> A related question: Does anyone know which (polished) metal has the
>> highest reflectance in the visible range 380-700nm?
>>
>> I know Al, Ag and perhaps Hg are good candidates, but I want to know
>> which are the best contenders.
>>
>> Many thanks,
>
> See: http://www.llnl.gov/tid/lof/documents/pdf/244132.pdf
Many thanks Sam. So Ag seems to be the best. I wonder how Hg rates.
--
I.N. Galidakis --- http://ioannis.virtualcomposer2000.com/
----------------------------------------------------------
"There's ALWAYS a mistake somewhere"
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Date: 26 Jun 2007 04:38:25
From: Helpful person
Subject: Re: Plans for a Liquid Lunar Telescope
|
On Jun 26, 1:15 am, LarryG <larryg...@yahoo.com > wrote:
> On Jun 24, 9:45 pm, j...@specsol.spam.sux.com wrote:
>
> > In sci.physics LarryG <larryg...@yahoo.com> wrote:
>
> > > On Jun 24, 4:55 pm, j...@specsol.spam.sux.com wrote:
> > > > The problem with telescopes like this isn't so much gravity as it
> > > > is mechanical balance and bearings.
> > > Magnetic bearings provide frictionless, wear-free operation.
>
> > Friction isn't the problem, it's noise.
>
> Magnetic bearings use a magnetic field to separate a rotating
> surface from a fixed surface. With no direct contact, there is no
> means to mechanically couple vibration from one element to the
> other, such as ball-bearings might induce through rolling, or a
> journal bearing through friction.
>
> Cheers,
> Larry G.
Maybe not through direct friction but a magnetic bearing does not
isolate noise.
www.richardfisher.com
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Date: 26 Jun 2007 16:25:02
From:
Subject: Re: Plans for a Liquid Lunar Telescope
|
In sci.physics Helpful person <rrllff@yahoo.com > wrote:
> On Jun 26, 1:15 am, LarryG <larryg...@yahoo.com> wrote:
> > On Jun 24, 9:45 pm, j...@specsol.spam.sux.com wrote:
> >
> > > In sci.physics LarryG <larryg...@yahoo.com> wrote:
> >
> > > > On Jun 24, 4:55 pm, j...@specsol.spam.sux.com wrote:
> > > > > The problem with telescopes like this isn't so much gravity as it
> > > > > is mechanical balance and bearings.
> > > > Magnetic bearings provide frictionless, wear-free operation.
> >
> > > Friction isn't the problem, it's noise.
> >
> > Magnetic bearings use a magnetic field to separate a rotating
> > surface from a fixed surface. With no direct contact, there is no
> > means to mechanically couple vibration from one element to the
> > other, such as ball-bearings might induce through rolling, or a
> > journal bearing through friction.
> >
> > Cheers,
> > Larry G.
> Maybe not through direct friction but a magnetic bearing does not
> isolate noise.
There is also bearing "roughness". How many magnets do you need to
get optical quality "smoothness".
Note I'm not saying it is impossible, just difficult.
--
Jim Pennino
Remove .spam.sux to reply.
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Date: 26 Jun 2007 12:00:34
From: Uncle Al
Subject: Re: Plans for a Liquid Lunar Telescope
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jimp@specsol.spam.sux.com wrote:
>
> In sci.physics Helpful person <rrllff@yahoo.com> wrote:
> > On Jun 26, 1:15 am, LarryG <larryg...@yahoo.com> wrote:
> > > On Jun 24, 9:45 pm, j...@specsol.spam.sux.com wrote:
> > >
> > > > In sci.physics LarryG <larryg...@yahoo.com> wrote:
> > >
> > > > > On Jun 24, 4:55 pm, j...@specsol.spam.sux.com wrote:
> > > > > > The problem with telescopes like this isn't so much gravity as it
> > > > > > is mechanical balance and bearings.
> > > > > Magnetic bearings provide frictionless, wear-free operation.
> > >
> > > > Friction isn't the problem, it's noise.
> > >
> > > Magnetic bearings use a magnetic field to separate a rotating
> > > surface from a fixed surface. With no direct contact, there is no
> > > means to mechanically couple vibration from one element to the
> > > other, such as ball-bearings might induce through rolling, or a
> > > journal bearing through friction.
> > >
> > > Cheers,
> > > Larry G.
>
> > Maybe not through direct friction but a magnetic bearing does not
> > isolate noise.
>
> There is also bearing "roughness". How many magnets do you need to
> get optical quality "smoothness".
>
> Note I'm not saying it is impossible, just difficult.
Lunar regolith is filthy with micronized metallic iron. Could this be
bad for a magnetic bearing?
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/lajos.htm#a2
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Date: 26 Jun 2007 19:55:03
From:
Subject: Re: Plans for a Liquid Lunar Telescope
|
In sci.physics Uncle Al <UncleAl0@hate.spam.net > wrote:
> jimp@specsol.spam.sux.com wrote:
> >
> > In sci.physics Helpful person <rrllff@yahoo.com> wrote:
> > > On Jun 26, 1:15 am, LarryG <larryg...@yahoo.com> wrote:
> > > > On Jun 24, 9:45 pm, j...@specsol.spam.sux.com wrote:
> > > >
> > > > > In sci.physics LarryG <larryg...@yahoo.com> wrote:
> > > >
> > > > > > On Jun 24, 4:55 pm, j...@specsol.spam.sux.com wrote:
> > > > > > > The problem with telescopes like this isn't so much gravity as it
> > > > > > > is mechanical balance and bearings.
> > > > > > Magnetic bearings provide frictionless, wear-free operation.
> > > >
> > > > > Friction isn't the problem, it's noise.
> > > >
> > > > Magnetic bearings use a magnetic field to separate a rotating
> > > > surface from a fixed surface. With no direct contact, there is no
> > > > means to mechanically couple vibration from one element to the
> > > > other, such as ball-bearings might induce through rolling, or a
> > > > journal bearing through friction.
> > > >
> > > > Cheers,
> > > > Larry G.
> >
> > > Maybe not through direct friction but a magnetic bearing does not
> > > isolate noise.
> >
> > There is also bearing "roughness". How many magnets do you need to
> > get optical quality "smoothness".
> >
> > Note I'm not saying it is impossible, just difficult.
> Lunar regolith is filthy with micronized metallic iron. Could this be
> bad for a magnetic bearing?
Could well be for something that is going to take micrometer manufacturing
tolerances and a lot better balance than you get at the tire store.
--
Jim Pennino
Remove .spam.sux to reply.
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Date: 25 Jun 2007 22:40:10
From: The Ghost In The Machine
Subject: Re: Plans for a Liquid Lunar Telescope
|
In sci.physics, Sam Wormley
<swormley1@mchsi.com >
wrote
on Sun, 24 Jun 2007 20:05:00 GMT
<467ECE6C.2010307@mchsi.com >:
> Plans for a Liquid Lunar Telescope
> http://www.universetoday.com/2007/06/21/plans-for-a-liquid-lunar-telescope/
>
> NASA-funded researchers are working on a clever technology that could
> deploy a gigantic telescope made from rotating liquid\u2026 on the
> Moon! It sounds like science fiction, but they've gotten smaller
> prototypes to work, and the technology should work even better on the
> lower lunar gravity.
>
> Here's how it works. Astronauts would deliver the observatory (all
> folded up) to the Moon during one of their upcoming "return to the
> Moon" missions. It would unfold into the shape of a telescope mirror
> made of mesh. The astronauts then pour a reflective liquid onto the
> mesh. The mesh rotates coating the entire surface in the liquid.
> Don't worry about the liquid dripping through the mesh, it actually
> gets held in place by surface tension.
>
> As telescopes go, this would be a whopper. The current plans call for
> a 20-metre mirror, but it could theoretically get as big as
> 100-metres across. This would provide 1000 times the observing power
> as the James Webb Space Telescope, which still won't launch for a few
> more years. That gives it the power to look right back to the very
> edge of the observable Universe, and see the first generations of
> stars forming.
>
> Now there's a reason to send humans back to the Moon.
>
To do this right would require the telescope to be placed
on the far side of Luna (so that Earth's interference
is blocked). Carefully shielded cables might be used to
transport the signal from luna firma to a small antenna
pointed at terra firma.
One could also envision several of these on the far side,
a la the Very Large Radio Array (?), which is spread
out over a wide area and can do various things a single
telescope simply can't do.
There is also the little problem of what liquids to use.
--
#191, ewill3@earthlink.net
New Technology? Not There. No Thanks.
--
Posted via a free Usenet account from http://www.teranews.com
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Date: 26 Jun 2007 12:33:33
From: Sam Wormley
Subject: Re: Plans for a Liquid Lunar Telescope
|
The Ghost In The Machine wrote:
>
> To do this right would require the telescope to be placed
> on the far side of Luna (so that Earth's interference
> is blocked). Carefully shielded cables might be used to
> transport the signal from luna firma to a small antenna
> pointed at terra firma.
Optical telescope--what interference?
>
> One could also envision several of these on the far side,
> a la the Very Large Radio Array (?), which is spread
> out over a wide area and can do various things a single
> telescope simply can't do.
>
> There is also the little problem of what liquids to use.
>
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Date: 27 Jun 2007 08:22:03
From: The Ghost In The Machine
Subject: Re: Plans for a Liquid Lunar Telescope
|
In sci.physics, Sam Wormley
<swormley1@mchsi.com >
wrote
on Tue, 26 Jun 2007 12:33:33 GMT
<xI7gi.1517$Fc.756@attbi_s21 >:
> The Ghost In The Machine wrote:
>
>>
>> To do this right would require the telescope to be placed
>> on the far side of Luna (so that Earth's interference
>> is blocked). Carefully shielded cables might be used to
>> transport the signal from luna firma to a small antenna
>> pointed at terra firma.
>
> Optical telescope--what interference?
Hmmm...good point, and even radio telescopes might not
be too bad off on near side, unless one is aiming it at
things that the Earth is about to occlude.
>
>>
>> One could also envision several of these on the far side,
>> a la the Very Large Radio Array (?), which is spread
>> out over a wide area and can do various things a single
>> telescope simply can't do.
>>
>> There is also the little problem of what liquids to use.
>>
>
--
#191, ewill3@earthlink.net
/dev/signature: No such file or directory
--
Posted via a free Usenet account from http://www.teranews.com
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Date: 25 Jun 2007 05:55:16
From: Shadowland
Subject: Re: Plans for a Liquid Lunar Telescope
|
On Jun 24, 10:35 pm, Helpful person <rrl...@yahoo.com > wrote:
> This is not a new idea. Mercury was used in a rotating bath to create
> a parabola many years ago. I can't remember the details or exactly
> when, but it was probably in the 1700s.
Oh yeah I remember a mercury telescope project in I believe Popular
Science Mag (or what is Astrnomy Mag) many years back.
Put mercury in a pan, spin it...presto...instant parabolic mirror !
Vary the focal length by adjusting the rpm.
Of course you can only look straight up...
Any vibration ruins the view....
And if you expose yourself to enough mercury, you begin to drool and
watch more and more television, forget how to tie your shoe strings
and have children with 2-3 heads.
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Date: 24 Jun 2007 19:35:00
From: Helpful person
Subject: Re: Plans for a Liquid Lunar Telescope
|
On Jun 24, 4:05 pm, Sam Wormley <sworml...@mchsi.com > wrote:
> Plans for a Liquid Lunar Telescope
> http://www.universetoday.com/2007/06/21/plans-for-a-liquid-lunar-tele...
>
> NASA-funded researchers are working on a clever technology that could
> deploy a gigantic telescope made from rotating liquid\u2026 on the
> Moon! It sounds like science fiction, but they've gotten smaller
> prototypes to work, and the technology should work even better on the
> lower lunar gravity.
>
> Here's how it works. Astronauts would deliver the observatory (all
> folded up) to the Moon during one of their upcoming "return to the
> Moon" missions. It would unfold into the shape of a telescope mirror
> made of mesh. The astronauts then pour a reflective liquid onto the
> mesh. The mesh rotates coating the entire surface in the liquid.
> Don't worry about the liquid dripping through the mesh, it actually
> gets held in place by surface tension.
>
> As telescopes go, this would be a whopper. The current plans call for
> a 20-metre mirror, but it could theoretically get as big as
> 100-metres across. This would provide 1000 times the observing power
> as the James Webb Space Telescope, which still won't launch for a few
> more years. That gives it the power to look right back to the very
> edge of the observable Universe, and see the first generations of
> stars forming.
>
> Now there's a reason to send humans back to the Moon.
This is not a new idea. Mercury was used in a rotating bath to create
a parabola many years ago. I can't remember the details or exactly
when, but it was probably in the 1700s.
www.richardfisher.com
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Date: 25 Jun 2007 02:45:03
From:
Subject: Re: Plans for a Liquid Lunar Telescope
|
In sci.physics Helpful person <rrllff@yahoo.com > wrote:
> On Jun 24, 4:05 pm, Sam Wormley <sworml...@mchsi.com> wrote:
> > Plans for a Liquid Lunar Telescope
> > http://www.universetoday.com/2007/06/21/plans-for-a-liquid-lunar-tele...
> >
> > NASA-funded researchers are working on a clever technology that could
> > deploy a gigantic telescope made from rotating liquid\u2026 on the
> > Moon! It sounds like science fiction, but they've gotten smaller
> > prototypes to work, and the technology should work even better on the
> > lower lunar gravity.
> >
> > Here's how it works. Astronauts would deliver the observatory (all
> > folded up) to the Moon during one of their upcoming "return to the
> > Moon" missions. It would unfold into the shape of a telescope mirror
> > made of mesh. The astronauts then pour a reflective liquid onto the
> > mesh. The mesh rotates coating the entire surface in the liquid.
> > Don't worry about the liquid dripping through the mesh, it actually
> > gets held in place by surface tension.
> >
> > As telescopes go, this would be a whopper. The current plans call for
> > a 20-metre mirror, but it could theoretically get as big as
> > 100-metres across. This would provide 1000 times the observing power
> > as the James Webb Space Telescope, which still won't launch for a few
> > more years. That gives it the power to look right back to the very
> > edge of the observable Universe, and see the first generations of
> > stars forming.
> >
> > Now there's a reason to send humans back to the Moon.
> This is not a new idea. Mercury was used in a rotating bath to create
> a parabola many years ago. I can't remember the details or exactly
> when, but it was probably in the 1700s.
Still used.
http://www.astro.ubc.ca/LMT/lzt/index.html
It takes non-trivial engineering to make one work.
--
Jim Pennino
Remove .spam.sux to reply.
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Date: 24 Jun 2007 21:55:03
From:
Subject: Re: Plans for a Liquid Lunar Telescope
|
In sci.physics Sam Wormley <swormley1@mchsi.com > wrote:
> Plans for a Liquid Lunar Telescope
> http://www.universetoday.com/2007/06/21/plans-for-a-liquid-lunar-telescope/
> NASA-funded researchers are working on a clever technology that could
> deploy a gigantic telescope made from rotating liquid\u2026 on the
> Moon! It sounds like science fiction, but they've gotten smaller
> prototypes to work, and the technology should work even better on the
> lower lunar gravity.
> Here's how it works. Astronauts would deliver the observatory (all
> folded up) to the Moon during one of their upcoming "return to the
> Moon" missions. It would unfold into the shape of a telescope mirror
> made of mesh. The astronauts then pour a reflective liquid onto the
> mesh. The mesh rotates coating the entire surface in the liquid.
> Don't worry about the liquid dripping through the mesh, it actually
> gets held in place by surface tension.
> As telescopes go, this would be a whopper. The current plans call for
> a 20-metre mirror, but it could theoretically get as big as
> 100-metres across. This would provide 1000 times the observing power
> as the James Webb Space Telescope, which still won't launch for a few
> more years. That gives it the power to look right back to the very
> edge of the observable Universe, and see the first generations of
> stars forming.
> Now there's a reason to send humans back to the Moon.
The problem with telescopes like this isn't so much gravity as it
is mechanical balance and bearings.
Any rumble in the bearings and your optical surface turns to crap,
though the idea works well for things like heliostats that don't
require a sharp image.
Plus you need a big ass, really flat mirror if you want to look in
any direction other than straight up.
--
Jim Pennino
Remove .spam.sux to reply.
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Date: 24 Jun 2007 14:46:01
From: Ian Parker
Subject: Re: Plans for a Liquid Lunar Telescope
|
On 24 Jun, 21:05, Sam Wormley <sworml...@mchsi.com > wrote:
> Plans for a Liquid Lunar Telescope
> http://www.universetoday.com/2007/06/21/plans-for-a-liquid-lunar-tele...
>
> NASA-funded researchers are working on a clever technology that could
> deploy a gigantic telescope made from rotating liquid\u2026 on the
> Moon! It sounds like science fiction, but they've gotten smaller
> prototypes to work, and the technology should work even better on the
> lower lunar gravity.
>
> Here's how it works. Astronauts would deliver the observatory (all
> folded up) to the Moon during one of their upcoming "return to the
> Moon" missions. It would unfold into the shape of a telescope mirror
> made of mesh. The astronauts then pour a reflective liquid onto the
> mesh. The mesh rotates coating the entire surface in the liquid.
> Don't worry about the liquid dripping through the mesh, it actually
> gets held in place by surface tension.
>
> As telescopes go, this would be a whopper. The current plans call for
> a 20-metre mirror, but it could theoretically get as big as
> 100-metres across. This would provide 1000 times the observing power
> as the James Webb Space Telescope, which still won't launch for a few
> more years. That gives it the power to look right back to the very
> edge of the observable Universe, and see the first generations of
> stars forming.
>
> Now there's a reason to send humans back to the Moon.
I still think an interferometer floating in space would be better.
What has emerged duping the "space age" is the fact that it is
possible to have ultra stable unmanned platforms. An interferometer
could be many kilometers (effective) in size.
LISA the gravitational wave detector is another example of ultra
stability.
- Ian Parker
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