Tomorrow's Monster Telescopes

An interesting article in April's Sky and Tel, Tomorrow's Monster
Telescopes.

A few comments in the article got me thinking.

"The Aperture fever that amateur astronomers often suffer afflicts
professionals too."

"If Extremely Large Telescopes do move beyond the Earth, it's anyones
guess to their size and structure."

Assume that some day unlimited funding and technology will be
available, and that we have the ability to build instruments as big
and optically perfect as we could possible ever want. (Visual light.
Just in case this question develops into a meaningful thread.)

Could an instrument be built where it could be said that no more
useful information can be obtained by building larger?

Would anyone care to speculate how large that instrument would be?

What would that telescope be capable doing?

Lets also assume this to be cloudy night, wishful sort of thinking
and that there's no reason for anyone to get their nose out of joint
because they don't like the question.

LdB

On Mar 9, 1:57 pm, L D'Bonnie wrote:
An interesting article in April's Sky and Tel, Tomorrow's Monster
Telescopes.

A few comments in the article got me thinking.

"The Aperture fever that amateur astronomers often suffer afflicts
professionals too."

"If Extremely Large Telescopes do move beyond the Earth, it's anyones
guess to their size and structure."


I too saw that cover, and the competing mag with 'Is this the shape of
the universe?', both of which caught my eye- yet neither did I
purchase.
(It was touch & go for a min. though.)

Still, it got me to wondering how much a larger mirror would be useful
vs. many smaller mirrors in a group, esp. something built down here on
the ground.

I would say improvements will better be gained by making a 'Super
Hubble' orbiting telescope instead, and beaming the images back to a
ground station.

Not the same as having the actual electrons hit the back of your eye
but then.....


TBerk

L D'Bonnie wrote:
An interesting article in April's Sky and Tel, Tomorrow's Monster
Telescopes.

A few comments in the article got me thinking.

"The Aperture fever that amateur astronomers often suffer afflicts
professionals too."

"If Extremely Large Telescopes do move beyond the Earth, it's anyones
guess to their size and structure."

Assume that some day unlimited funding and technology will be
available, and that we have the ability to build instruments as big
and optically perfect as we could possible ever want. (Visual light.
Just in case this question develops into a meaningful thread.)

Could an instrument be built where it could be said that no more
useful information can be obtained by building larger?

Would anyone care to speculate how large that instrument would be?

What would that telescope be capable doing?

Lets also assume this to be cloudy night, wishful sort of thinking
and that there's no reason for anyone to get their nose out of joint
because they don't like the question.

At the point that the telescope is large enough that the limit to its
resolution is the atmosphere of the alien world that its looking at,
then its big enough.
:-)


Shawn

On Sun, 09 Mar 2008 15:57:51 -0500, L D'Bonnie wrote:

Could an instrument be built where it could be said that no more
useful information can be obtained by building larger?

From a practical standpoint, I'd say no. A bigger aperture means more
resolution, of course. But it also means more light, and that means the
ability to record more rapid events.

In theory, you don't need more resolution when you reach the point where
you can resolve something the wavelength of your light at the edge of
the observable Universe. So in terms of resolution, that could be
considered to define an upper limit on aperture. But somehow I don't
think you were considering mirrors the size of galaxy clusters g.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

--
Posted via a free Usenet account from http://www.teranews.com

In article ,
L D'Bonnie wrote:
An interesting article in April's Sky and Tel, Tomorrow's Monster
Telescopes.

A few comments in the article got me thinking.

"The Aperture fever that amateur astronomers often suffer afflicts
professionals too."

"If Extremely Large Telescopes do move beyond the Earth, it's anyones
guess to their size and structure."

Assume that some day unlimited funding and technology will be
available, and that we have the ability to build instruments as big
and optically perfect as we could possible ever want. (Visual light.
Just in case this question develops into a meaningful thread.)

Could an instrument be built where it could be said that no more
useful information can be obtained by building larger?

With unlimited funding and technology available, why would one limit
oneself to just build a huge telescope? Why not instead build e.g.
a very large number of vehicles which all instantly could travel to
any place in the universe?

Or perhaps one could then transform the universe into something we
would prefer over the existing universe..... why just observe when
we actually can change things?

And, while we're at it, with unlimited technology, why would a telescope
have to be huge? Why not instead build e.g. a small pocket scope
with capabilities exceeding anything we could ever dream of? That
scope would then be able to e.g. resolve small details (e.g. molecules)
on planets in another galaxy! And it would be cheap enough for each
kid to be able to afford one.... compare with e.g. computers, where
the early dinosaur computers did cost millions and each required a
staff of trained engineers to run - today, a kid can easily buy a
home computer with capabilities far exceeding those early dinosaurs...

With truly unlimited funding and unlimited technology, each of these
things would be quite feasible. The reason this is a fantasy is of
course that in real life, both funding and technology will always have
limits. Even if funding would be unlimited, technology for instance
is always limited by the natural laws.




Would anyone care to speculate how large that instrument would be?

What would that telescope be capable doing?

Lets also assume this to be cloudy night, wishful sort of thinking
and that there's no reason for anyone to get their nose out of joint
because they don't like the question.

LdB


--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stjarnhimlen dot se
WWW: http://stjarnhimlen.se/

In article ,
Chris L Peterson wrote:
On Sun, 09 Mar 2008 15:57:51 -0500, L D'Bonnie wrote:

Could an instrument be built where it could be said that no more
useful information can be obtained by building larger?

From a practical standpoint, I'd say no. A bigger aperture means more
resolution, of course. But it also means more light, and that means the
ability to record more rapid events.

In theory, you don't need more resolution when you reach the point where
you can resolve something the wavelength of your light at the edge of
the observable Universe. So in terms of resolution, that could be
considered to define an upper limit on aperture. But somehow I don't
think you were considering mirrors the size of galaxy clusters g.

You're thinking in the limits of current technology. If truly
'unlimited technlogy' really was available, it could produce a small
pocket scope able to resolve much smaller objects than a light wavelength,
at the other end of the universe - and that scope would be cheap enough
for kids to be able to afford it.

Consider today's pocket computers which have capabilities far exceeding the
early dinosaur computers of the 1950's ..... truly 'unlimited technology'
would of course be able to bring a similar revolution in telescopes.
How would they work? I have absolutely no idea -- according to our
current understainding, such a device is impossible. But that's just
because our technology is LIMITED by the natural laws. Truly unlimited
technology would not have such limits....

_______________________________________________ __

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

--
Posted via a free Usenet account from http://www.teranews.com



--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stjarnhimlen dot se
WWW: http://stjarnhimlen.se/

On Mar 9, 1:57 pm, L D'Bonnie wrote:

Could an instrument be built where it could be said that no more
useful information can be obtained by building larger?

I'm not sure, but I remember once doing a little calculation.

How big would a telescope be, so that a planet, the size of Earth,
orbiting Alpha Centauri, would show as much detail as Mars, viewed
from Earth, using a six-inch telescope?

The answer is - thirty *miles* in diameter. So, I'd say we have a way
to go.

John Savard

On Mon, 10 Mar 2008 07:43:02 GMT, (Paul Schlyter) wrote:

You're thinking in the limits of current technology. If truly
'unlimited technlogy' really was available, it could produce a small
pocket scope able to resolve much smaller objects than a light wavelength,
at the other end of the universe - and that scope would be cheap enough
for kids to be able to afford it.

Consider today's pocket computers which have capabilities far exceeding the
early dinosaur computers of the 1950's ..... truly 'unlimited technology'
would of course be able to bring a similar revolution in telescopes.
How would they work? I have absolutely no idea -- according to our
current understainding, such a device is impossible. But that's just
because our technology is LIMITED by the natural laws. Truly unlimited
technology would not have such limits....

There's a difference between "unlimited technology" and "magic".
Unlimited technology doesn't mean you can do anything, it means that the
laws of nature are your only limits (not, for instance, engineering
limitations). There's absolutely no reason to think that a pocket sized,
optical telescope can achieve arbitrarily fine resolution. And it
certainly can only collect the photons that cross its path, which isn't
very many.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

--
Posted via a free Usenet account from http://www.teranews.com

Quadibloc wrote:
On Mar 9, 1:57 pm, L D'Bonnie wrote:

Could an instrument be built where it could be said that no more
useful information can be obtained by building larger?

I'm not sure, but I remember once doing a little calculation.

How big would a telescope be, so that a planet, the size of Earth,
orbiting Alpha Centauri, would show as much detail as Mars, viewed
from Earth, using a six-inch telescope?

The answer is - thirty *miles* in diameter. So, I'd say we have a way
to go.

John Savard

Kepler couldn't even begin to dream of supercomputers. As I recall
he he used blocks of wood to do his calculations, then planed them
down so he could use the surface again. What did teraflops mean to
him?

How big could Galileo have built? Something like Hubble was a tad
out of his reach.

A telescope thirty miles in diameter? With funding and desire we
could well be in the planning stages of one now.

Seriously though, if you could resolve the disk of a planet at
that distance, could you read a newspaper headline with an instrument
twice that size? Is the only limit to resolution the practical
limits of the size of an instrument?

Mirrors the size of galaxy clusters would be a bit impractical. It
would take thousands of years for the light to come to focus, and
then you would still have to wait a week to get the film back from
the drugstore. (I have yet to buy a DSLR)

LdB

On Mon, 10 Mar 2008 15:40:24 -0500, L D'Bonnie wrote:

Mirrors the size of galaxy clusters would be a bit impractical. It
would take thousands of years for the light to come to focus, and
then you would still have to wait a week to get the film back from
the drugstore. (I have yet to buy a DSLR)

Millions of years. But since it would also take millions of years to
construct something that large, I guess the builders will have become
accustomed to working on those time scales.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

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