Naked Science Forum

General Discussion & Feedback => Just Chat! => Topic started by: syhprum on 17/07/2021 09:00:38

Title: Were spare versions of Hubble built?
Post by: syhprum on 17/07/2021 09:00:38
The Hubble telescope started life during the "cold war" as a modified version of a high technology reconnaissance satellite system.
I understud about six units were built but never put into service.
As the cost consists mostly of the research and develop time would it not have been expedient to have built at least one spare
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 17/07/2021 15:26:03
I understand that there was a second mirror (at least- there may also have been other spares) made by a different manufacturer- Kodak.
Both mirrors were "flight ready" in time for use.
They chose the mirror made by the company with the better reputation- Perkin Elmer.
In doing so, they picked the one which wasn't ground correctly.
When the problem with Hubble was discovered, they tested the other mirror. It was in spec.

https://airandspace.si.edu/collection-objects/hubble-space-telescope-backup-mirror/nasm_A20010288000

Title: Re: Were spare versions of Hubble built?
Post by: Europa on 19/07/2021 16:04:16
The Hubble telescope started life during the "cold war" as a modified version of a high technology reconnaissance satellite system.
I understud about six units were built but never put into service.
As the cost consists mostly of the research and develop time would it not have been expedient to have built at least one spare

Actually the reason that the Hubble's mirror was defective is because the Hubble was not meant to view the stars but meant to view the Earth as a spy satellite would, or read Gorbachev's mail in Gorbachev's hand, as it may be.  Not sure if there were more as the mirrors for these things are very hard to produce
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 16:22:06
The Hubble telescope started life during the "cold war" as a modified version of a high technology reconnaissance satellite system.
I understud about six units were built but never put into service.
As the cost consists mostly of the research and develop time would it not have been expedient to have built at least one spare

Actually the reason that the Hubble's mirror was defective is because the Hubble was not meant to view the stars but meant to view the Earth as a spy satellite would, or read Gorbachev's mail in Gorbachev's hand, as it may be.  Not sure if there were more as the mirrors for these things are very hard to produce
That's nonsense from a number of points of view, not least that, a telescope is a telescope. You grind the primary mirror to a parabola whether you plan to point it up or down.
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 19/07/2021 16:52:04
The Hubble telescope started life during the "cold war" as a modified version of a high technology reconnaissance satellite system.
I understud about six units were built but never put into service.
As the cost consists mostly of the research and develop time would it not have been expedient to have built at least one spare

Actually the reason that the Hubble's mirror was defective is because the Hubble was not meant to view the stars but meant to view the Earth as a spy satellite would, or read Gorbachev's mail in Gorbachev's hand, as it may be.  Not sure if there were more as the mirrors for these things are very hard to produce
That's nonsense from a number of points of view, not least that, a telescope is a telescope. You grind the primary mirror to a parabola whether you plan to point it up or down.

The fact is that a telescope is not a telescope, this is true because the mirror must be ground to exactly a certain specification depending on what it intends to focus on.  The Hubble was a complete failure after launch because it could not focus on the stars and new computer programming was installed to correct for the flaw.  You may or may not remember this, I do.  When launched the Hubble was only able to focus on the Earth and not the stars.  Look it up, it's all there.
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 17:32:36
new computer programming was installed to correct for the flaw.  You may or may not remember this, I do. 
I remember what they actually did to fix the flaw.

https://esahubble.org/about/general/instruments/costar/

As you say,
  Look it up, it's all there.

The primary mirror of a telescope is ground and polished to a paraboloid.
It does not matter if you want to use it as a spy satellite (which is, indeed, where Perkin Elmer got their "expertise") or an astronomical telescope.


You have repeatedly shown that you do not know what you are talking about.
Why not stop wasting bandwidth?
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 19/07/2021 17:40:52
new computer programming was installed to correct for the flaw.  You may or may not remember this, I do. 
I remember what they actually did to fix the flaw.

https://esahubble.org/about/general/instruments/costar/

As you say,
  Look it up, it's all there.

The primary mirror of a telescope is ground and polished to a paraboloid.
It does not matter if you want to use it as a spy satellite (which is, indeed, where Perkin Elmer got their "expertise") or an astronomical telescope.


You have repeatedly shown that you do not know what you are talking about.
Why not stop wasting bandwidth?

The fact remains that when the Hubble was launched that a supposed serious flaw in the mirror made it IMPOSSIBLE to focus to the stars.  So the satellite was a complete waste of money, except that the Soviets knew that it was focusing on them which was the point.  So focusing on Earth was the purpose of the Hubble, the designers hoped that it would also function on the stars however they had to install new parts to achieve the secondary goal of astronomy.  You do know that the space shuttle primarily launched military satellites right and that science was just a back seat afterthought right?
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 17:54:59
When launched the Hubble was only able to focus on the Earth
Nope. That's just wrong.
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 19/07/2021 18:01:26
When launched the Hubble was only able to focus on the Earth
Nope. That's just wrong.

Again when the Hubble was launched it was not able to focus correctly until new optics parts were manually installed in orbit.  It's there, you can search it on your own I presume
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 18:04:50
The fact remains that when the Hubble was launched that a supposed serious flaw in the mirror made it IMPOSSIBLE to focus to the stars.
It also made it impossible to focus on Earth (or the Moon for that matter).

It was a screw up, not a conspiracy.
The Soviets knew that the West had spy satellites and we knew that they had them.
Your story makes no sense.
So focusing on Earth was the purpose of the Hubble
It could not do that.


If you think it could, then prove it.
the designers hoped that it would also function on the stars
Why do you claim that some of the best optical designers in the world- the ones who made spy satellite telescopes- were too stupid to realise that a bad telescope does not work?
If it won't give you a clear image of a star, it certainly won't give a clear image of a Russian Newspaper.

The mirror is 2.4 metres across.
The wavelength of light it uses (i.e. visible light) is about 1/2 million of a metre.
So the angular resolution is diffraction limited at about 1/4.8 million radians.
The height is about 550 Km
So the resolution on the ground can't possibly be better than about 0.1 metre.

Are you suggesting that Mr Gorbachev's mail was only ever in the form of advertising hoardings with letters a couple of feet high?

(And that he was in the habit of only reading it outside on sunny days)

Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 18:07:08
Again when the Hubble was launched it was not able to focus correctly until new optics parts were manually installed in orbit.  It's there, you can search it on your own I presume
And, since it could not focus on the Earth , it was not a spy satellite, was it?
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 19/07/2021 18:08:23
The fact remains that when the Hubble was launched that a supposed serious flaw in the mirror made it IMPOSSIBLE to focus to the stars.
It also made it impossible to focus on Earth (or the Moon for that matter).

It was a screw up, not a conspiracy.
The Soviets knew that the West had spy satellites and we knew that they had them.
Your story makes no sense.
So focusing on Earth was the purpose of the Hubble
It could not do that.


If you think it could, then prove it.
the designers hoped that it would also function on the stars
Why do you claim that some of the best optical designers in the world- the ones who made spy satellite telescopes- were too stupid to realise that a bad telescope does not work?
If it won't give you a clear image of a star, it certainly won't give a clear image of a Russian Newspaper.

The mirror is 2.4 metres across.
The wavelength of light it uses (i.e. visible light) is about 1/2 million of a metre.
So the angular resolution is diffraction limited at about 1/4.8 million radians.
The height is about 550 Km
So the resolution on the ground can't possibly be better than about 0.1 metre.

Are you suggesting that Mr Gorbachev's mail was only ever in the form of advertising hoardings with letters a couple of feet high?

The Hubble mirror was the highest optic ever put in a spy satellite, perhaps someday it's Earth photos will be declassified.  It was also probably a failure as no others were ever launched as digital image capture was revolutionizing photography at this time
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 18:10:24
It's there, you can search it on your own I presume
I pointed it out to you.
I remember what they actually did to fix the flaw.

https://esahubble.org/about/general/instruments/costar/

You had come up with some silly idea about software fixing it.
You can do image deconvolution, but it' never as good as getting the damned thing in focus in the first place.
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 18:14:02
The Hubble mirror was the highest optic ever put in a spy satellite, perhaps someday it's Earth photos will be declassified. 
Well, if they are they won't be much good.
It's moving too fast; the pictures will be blurred.
You really don't know much about optics, do you?

https://earthsky.org/space/can-the-hubble-space-telescope-be-used-to-observe-earth/
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 18:15:15
digital image capture was revolutionizing photography at this time
You do know that Hubble is a digital camera, don't you?
They don't pop up there and put a new roll of film in it from time to time.
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 19/07/2021 18:16:10
It's there, you can search it on your own I presume
I pointed it out to you.
I remember what they actually did to fix the flaw.

https://esahubble.org/about/general/instruments/costar/

You had come up with some silly idea about software fixing it.
You can do image deconvolution, but it' never as good as getting the damned thing in focus in the first place.
I came up with nothing, as new optics and software were installed manually on the Hubble

https://www.nasa.gov/content/hubbles-mirror-flaw

If you read you will see that nearsighted is mentioned, so the new optics allowed for far sighting to the universe
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 19/07/2021 18:20:52
digital image capture was revolutionizing photography at this time
You do know that Hubble is a digital camera, don't you?
They don't pop up there and put a new roll of film in it from time to time.

The refinements to CCD Spectroscopy during this time frame made the instruments launched obsolete before being installed.  New optics do not require such large lenses as computer enhancements actually now do much of the focusing when in past generations the lens was 100 percent responsible for this. 

 
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 18:37:23
I came up with nothing,
You do realise this is a discussion forum, don't you?
Other people can see what you wrote.
They can see that you came up with this

new computer programming was installed to correct for the flaw. 

People are laughing at you.

If you read you will see that nearsighted is mentioned
Yes.
They say this
" replacement instruments that fixed the flaw much the same way a pair of glasses correct the vision of a near-sighted person"
Do you see that they say "in much the same way as"?
They do not say that the telescope was shortsighted.
They do actually say what the problem is here
https://www.nasa.gov/content/goddard/hubble-space-telescope-optics-system
"To remedy the spherical aberration".

And that's not a focussing defect. You can't change the position of the mirror and fix it like you can with shortsightedness.

Just because you don't understand the difference doesn't mean that there isn't one.


  New optics do not require such large lenses
They don't use lenses much.
They use mirrors.
computer enhancements actually now do much of the focusing
Only one of us has ever studied optics.
It is impossible to make a silk purse out of a sow's ear.
Yes, you can get the computer to fiddle with the image.
But fundamentally, you do much better if you have a better mirror in the first place.
And astronomers- even amateur ones- have been grinding "diffraction limited" mirrors for a long time.

It's easy to get an essentially perfect mirror.
It's very hard to put stuff in space.
Why wouldn't you use the best available mirror?
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 19/07/2021 18:43:04
I came up with nothing,
You do realise this is a discussion forum, don't you?
Other people can see what you wrote.
They can see that you came up with this

new computer programming was installed to correct for the flaw.

People are laughing at you.

If you read you will see that nearsighted is mentioned
Yes.
They say this
" replacement instruments that fixed the flaw much the same way a pair of glasses correct the vision of a near-sighted person"
Do you see that they say "in much the same way as"?
They do not say that the telescope was shortsighted.
They do actually say what the problem is here
https://www.nasa.gov/content/goddard/hubble-space-telescope-optics-system
"To remedy the spherical aberration".

And that's not a focussing defect. You can't change the position of the mirror and fix it like you can with shortsightedness.

Just because you don't understand the difference doesn't mean that there isn't one.


  New optics do not require such large lenses
They don't use lenses much.
They use mirrors.
computer enhancements actually now do much of the focusing
Only one of us has ever studied optics.
It is impossible to make a silk purse out of a sow's ear.
Yes, you can get the computer to fiddle with the image.
But fundamentally, you do much better if you have a better mirror in the first place.
And astronomers- even amateur ones- have been grinding "diffraction limited" mirrors for a long time.

It's easy to get an essentially perfect mirror.
It's very hard to put stuff in space.
Why wouldn't you use the best available mirror?
Actually cameras use both lenses and mirrors and the Hubble was both a telescope and a camera.  Nothing you might have studied says any different.
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 18:51:37
Actually cameras use both lenses and mirrors and the Hubble was both a telescope and a camera.
I didn't say otherwise, did I?

It's perfectly possible to build a camera with only mirrors rather than lenses.
https://en.wikipedia.org/wiki/Catoptrics

What I said was
They don't use lenses much.
They use mirrors.
Hubble's mirror has a mass of about 800 Kg, what do you think the lenses weigh?
What's your definition of "much"?
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 19/07/2021 19:04:12
Actually cameras use both lenses and mirrors and the Hubble was both a telescope and a camera.
I didn't say otherwise, did I?

It's perfectly possible to build a camera with only mirrors rather than lenses.
https://en.wikipedia.org/wiki/Catoptrics

What I said was
They don't use lenses much.
They use mirrors.
Hubble's mirror has a mass of about 800 Kg, what do you think the lenses weigh?
What's your definition of "much"?

Again the Hubble is both a camera intended to photograph the Kremlin and a telescope.  The Hubble was totally unable to focus on the the universe after being launched because it was primarily designed to read the Kremlin's mail.  What I think any of this weighs is just distracting an irrelevant
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 19:12:06
Again the Hubble is both a camera intended to photograph the Kremlin
It does not matter how many times you say it, the claim isn't just wrong, it is impossible.
Hubble was moving too fast to get decent pictures of the Earth.
The sensors are also very wrong; they are designed for dim objects, not bright ones.

What is your purpose in coming here and being loudly wrong?

I presume you think this
https://en.wikipedia.org/wiki/James_Webb_Space_Telescope
doesn't exist.
The mirror is about 3 times bigger than Hubble's, but it's going to be about 2000 times further from Earth, so it's about a thousand times worse as a spy satellite, and it uses Infrared which reduces the resolution even further.
It won't be able to see stuff on Earth unless it's about a hundred metres across.


Are you still saying

science was just a back seat afterthought
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 19/07/2021 19:20:25
Again the Hubble is both a camera intended to photograph the Kremlin
It does not matter how many times you say it, the claim isn't just wrong, it is impossible.
Hubble was moving too fast to get decent pictures of the Earth.
The sensors are also very wrong; they are designed for dim objects, not bright ones.

What is your purpose in coming here and being loudly wrong?

I presume you think this
https://en.wikipedia.org/wiki/James_Webb_Space_Telescope
doesn't exist.

If you presume that I read wiki you are wrong.  Now as for the Hubble being successful at it's objectives one might ask that if it were, why was no replacement ever launched.  See I never claimed that it was successful as it was a failure at launch and had to be serviced in space to be able to do anything, as far as we know anyway.  So as for how clear the classified images are of the Kremlin I can not testify too. 
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 19:52:33
Now as for the Hubble being successful at it's objectives one might ask that if it were, why was no replacement ever launched. 
Because it was a success.
Now, decade later we have better kit so we are launching what is generally seen as the successor.

If you presume that I read wiki you are wrong. 
Pity, you might learn something.
So as for how clear the classified images are of the Kremlin I can not testify too. 
You don't need to declassify them.
The laws of physics tell you that , with a mirror that size, the best possible resolution at ground level is about 0.1 metres (and the specification says about 0.3 metres).

But. as I keep pointing out, and you keep ignoring, it's moving too fast.
All you would get is a blur.

Do you not understate that?

It's not a matter of it being a military secret; it s a matter of physical impossibility.
If you wanted a picture of the kremlin, you would do better to buy a postcard of it than to use Hubble.


Why are you posting this tosh?

Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 19:56:59
I never claimed that it was successful
No. That would be a mater of opinion anyway.
But you did claim that it did not work because it was designed as a spy camera.
However the laws of physics- the motion blurring and theoretical diffraction limited resolution-  as well as the instrumentation, make it clear that it was not.

And, since it's not a spy satellite, it wasn't designed as one (it would be a stupidly bad design) then we know it didn't fail "because" it was built as one.
So we know that there must have been a differed reason- a cock up is the most likely.

So, as I say, why are you posting conspiracy nonsense?
Did you not realise this was a science site?
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 19/07/2021 20:08:12
I never claimed that it was successful
No. That would be a mater of opinion anyway.
But you did claim that it did not work because it was designed as a spy camera.
However the laws of physics- the motion blurring and theoretical diffraction limited resolution-  as well as the instrumentation, make it clear that it was not.

And, since it's not a spy satellite, it wasn't designed as one (it would be a stupidly bad design) then we know it didn't fail "because" it was built as one.
So we know that there must have been a differed reason- a cock up is the most likely.

So, as I say, why are you posting conspiracy nonsense?
Did you not realise this was a science site?
Funny how the people who designed the Hubble did not have the knowledge that you claim too have.  Which somehow fails to make any sense.  So as I said the Hubble was a 100 percent complete astronomical failure after launch as it was not intended to be a telescope, but to look into the Kremlins windows as it's primary task.  You may however be correct that this never worked properly as many things need to be tested to be confirmed failures. 
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 20:24:10
Funny how the people who designed the Hubble did not have the knowledge that you claim too have.
What "knowledge " are you talking about?
So as I said the Hubble was a 100 percent complete astronomical failure after launch as it was not intended to be a telescope
No. It failed because they screwed up.
it was not intended to be a telescope, but to look into the Kremlins windows as it's primary task.
It could not do this.
The resolution would not be good enough, and the image would be blurred because the telescope is moving so fast.
So either they built it for this primary task, but never had a hope in hell of it doing its job, or they built it as an astronomical telescope- which (once they found a work-round for the cock-up) it did very well.

Why are you not paying attention to the simple fact that the mirror is not big enough to see details smaller than a foot or so from that altitude?

Do you understand that there is a fundamental limit to the resolution of a telescope- it was worked out a long time ago.
https://courses.lumenlearning.com/physics/chapter/27-6-limits-of-resolution-the-rayleigh-criterion/

The people at Perkin Elmer who built Hubble knew about this- partly because they weren't uneducated idiots- but mainly because they were in the business of making spy satellites.
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 19/07/2021 20:28:55
Funny how the people who designed the Hubble did not have the knowledge that you claim too have.
They had the knowledge; they just screwed up a measurement.
So as I said the Hubble was a 100 percent complete astronomical failure after launch as it was not intended to be a telescope
because they screwed up.
it was not intended to be a telescope, but to look into the Kremlins windows as it's primary task.
It could not do this.
The resolution would not be good enough, and the image would be blurred because the telescope is moving so fast.
So either they built it for this primary task, but never had a hope in hell of it doing its job, or they built it as an astronomical telescope- which (once they found a work-round for the cock-up) it did very well.

Why are you not paying attention to the simple fact that the mirror is not big enough to see details smaller than a foot or so from that altitude?

Do you understand that there is a fundamental limit to the resolution of a telescope- it was worked out a long time ago.
https://courses.lumenlearning.com/physics/chapter/27-6-limits-of-resolution-the-rayleigh-criterion/

The people at Perkin Elmer who built Hubble knew about this- partly because they weren't uneducated idiots- but mainly because they were in the business of making spy satellites.

LOL now you are claiming that the faulty mirror was built on purpose.

Technically you are correct because the mirror was not imperfect when pointed at the Earth, only when facing away from the Earth, the fault was that the onboard optics could not correct for imperfect focus when pointed to the universe.

Hey secretive military stuff like this was everywhere. Again you do know that NASA was launching and servicing military satellites with the shuttle not just doing experiments with rice
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 20:36:10
LOL now you are claiming that the faulty mirror was built on purpose.
No
I made it quite clear that they did not do it on purpose.

It failed because they screwed up.


So it looks like part of the problem here is your reading comprehension.
Do you really not understand that "screwed up" means made a mistake?

You also need to understand that a telescope primary mirror  is a telescope primary mirror . You grind the mirror to the same shape- a parabola- regardless of what you will point it at.

So, if they had made a spy satellite mirror, it would have had the same shape mirror as an astronomical telescope mirror.

But they messed it up.

Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 20:38:49
Technically you are correct because the mirror was not imperfect when pointed at the Earth, only when facing away from the Earth, the fault was that the onboard optics could not correct for imperfect focus when pointed to the universe.
If that was true (and it's impossible,by the way) ...
HOW WOULD YOU KNOW?
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 20:43:52
You forgot toanswer a few points.

Why are you not paying attention to the simple fact that the mirror is not big enough to see details smaller than a foot or so from that altitude?
So, as I say, why are you posting conspiracy nonsense?
Did you not realise this was a science site?
But. as I keep pointing out, and you keep ignoring, it's moving too fast.
All you would get is a blur.

Do you not understand that?


Are you suggesting that Mr Gorbachev's mail was only ever in the form of advertising hoardings with letters a couple of feet high?
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 19/07/2021 20:50:52
You forgot toanswer a few points.

Why are you not paying attention to the simple fact that the mirror is not big enough to see details smaller than a foot or so from that altitude?
So, as I say, why are you posting conspiracy nonsense?
Did you not realise this was a science site?
But. as I keep pointing out, and you keep ignoring, it's moving too fast.
All you would get is a blur.

Do you not understand that?


Are you suggesting that Mr Gorbachev's mail was only ever in the form of advertising hoardings with letters a couple of feet high?
My purpose is not to answer to your distraction points.  My purpose was to remind people that when launched that the Hubble space telescope was totally non functional because the mirror was ground to focus on the Earth which makes the Hubble just another spy satellite that took a few pictures of the Universe when it was not pointed at the Kremlin.
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 20:57:52
My purpose was to remind people that when launched that the Hubble space telescope was totally non functional because the mirror was ground to focus on the Earth which makes the Hubble just another spy satellite that took a few pictures of the Universe when it was not pointed at the Kremlin.
So, you came to a science page to say something which is obviously not true because the shape you grind the mirror is the same if you point it up or down- why do you imagine it would be different?

Why would you do that?

Incidentally, pointing out that you are wrong is not a distraction; it's science.
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 19/07/2021 21:12:01
My purpose was to remind people that when launched that the Hubble space telescope was totally non functional because the mirror was ground to focus on the Earth which makes the Hubble just another spy satellite that took a few pictures of the Universe when it was not pointed at the Kremlin.
So, you came to a science page to say something which is obviously not true because the shape you grind the mirror is the same if you point it up or down- why do you imagine it would be different?

Why would you do that?

Incidentally, pointing out that you are wrong is not a distraction; it's science.
Actually to focus light correctly bouncing off the near Earth as opposed to the infinity of the universe would require a slightly different parabolic curve in the mirror.  But you knew that already.
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 19/07/2021 21:51:44
Actually to focus light correctly bouncing off the near Earth as opposed to the infinity of the universe would require a slightly different parabolic curve in the mirror.  But you knew that already.

You seem to have read a book, but not really understood it.
The focal length of the HST is 57.6 metres.
The distance from the Earth is 540000 metres which is practically at infinity.


But you still miss the point.
If I want to change the focus of my camera from a foot away to take a picture of the Moon, I don't need to regrind the lens to a different shape.
I just move it slightly.
So. let's do the calculation.
First the easy one; how far away from the image sensor should the mirror be to take pictures at infinity- that's easy- it's the focal length

And now let's calculate how far it needs to be if we want to get a picture of the Earth (in spite on not having enough resolution, and the motion blurring making it pointless)
It's the lens formula (I know it's a mirror, but the maths is the same)
http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/lenseq.html
1/ o +1/i = 1/f
where f is the focal length  is the image distance and o is the object distance
OK We can rearrange that
1/o = 1/f - 1/i

f is the focal length 57.6 metres
 o is  the object distance- that's the distance to Earth  540000 metres


1/f =0.017636684
1/o = 0.000001851

so 1/i is the difference 0.017359...
and so i (the image distance) is 57.6061 metres.
So the change in focus is about 6 mm.

And they would have allowed for that variation when they built it-
Why wouldn't they?
It's not hard.
They would, of course, have to allow some focussing anyway because the focal length of the mirror (ironically) may not have been that precise.
They also needed to be able to change the focus because of requirements of different instruments within the 'scope.

So, if, as you seem to think, it was as simple focus error, they would have ben able to focus it.
No need for all the problems and embarrassment.


In particular if, as you seem to think, they wanted to be able to focus on the kremlin (it's pointless but never mind) and also on the stars, they would certainly have been able to do the same calculation I just did.


So, why are you saying they built the worlds biggest spy satellite,  disguised it as a science project (why?, by the way, the US military budget is so big that paying for Hubble wouldn't be a problem. Why not just be honest about it being a spy camera?) but they forgot that they would need to change focus?

Why do you think they were that stupid?

Your whole idea makes no sense.
If they wanted to spend that much to look at the Kremlin, they could have done a much better job- for a start you would choose a lower orbit. (or just bought a postcard.)
They didn't need to "disguise" it, they could have just kept it secret.


Title: Re: Were spare versions of Hubble built?
Post by: Just thinking on 19/07/2021 23:21:55
No the parabolic mirror is ground and polished to focus on any distance as the focus is achieved by the position of the detector. and in the case of the Hubble telescope as with most optical telescopes that is the optics are best suited to look into infinity. And infinity is according to the diameter of the mirror in relation to its resolution ability and in the case of the Hubble it is about 300 kilometres any closer than that will require some out focus.
Title: Re: Were spare versions of Hubble built?
Post by: Just thinking on 19/07/2021 23:45:13
The primary mirror of a telescope is ground and polished to a paraboloid.
It does not matter if you want to use it as a spy satellite (which is, indeed, where Perkin Elmer got their "expertise") or an astronomical telescope.


You have repeatedly shown that you do not know what you are talking about.
Why not stop wasting bandwidth?
We don't agree on much but you have this one no argument from me what a clown.
Title: Re: Were spare versions of Hubble built?
Post by: Just thinking on 19/07/2021 23:48:39
The primary mirror of a telescope is ground and polished to a paraboloid.
It does not matter if you want to use it as a spy satellite (which is, indeed, where Perkin Elmer got their "expertise") or an astronomical telescope.


You have repeatedly shown that you do not know what you are talking about.
Why not stop wasting bandwidth?
We don't agree on much but you have this one no argument from me what a clown.
Actually cameras use both lenses and mirrors and the Hubble was both a telescope and a camera.  Nothing you might have studied says any different.
Well if it didn't have a camera then they must have an astronaut up there looking throw a little eye pice.
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 19/07/2021 23:56:48
Actually to focus light correctly bouncing off the near Earth as opposed to the infinity of the universe would require a slightly different parabolic curve in the mirror.  But you knew that already.

You seem to have read a book, but not really understood it.
The focal length of the HST is 57.6 metres.
The distance from the Earth is 540000 metres which is practically at infinity.


But you still miss the point.
If I want to change the focus of my camera from a foot away to take a picture of the Moon, I don't need to regrind the lens to a different shape.
I just move it slightly.
So. let's do the calculation.
First the easy one; how far away from the image sensor should the mirror be to take pictures at infinity- that's easy- it's the focal length

And now let's calculate how far it needs to be if we want to get a picture of the Earth (in spite on not having enough resolution, and the motion blurring making it pointless)
It's the lens formula (I know it's a mirror, but the maths is the same)
http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/lenseq.html
1/ o +1/i = 1/f
where f is the focal length  is the image distance and o is the object distance
OK We can rearrange that
1/o = 1/f - 1/i

f is the focal length 57.6 metres
 o is  the object distance- that's the distance to Earth  540000 metres


1/f =0.017636684
1/o = 0.000001851

so 1/i is the difference 0.017359...
and so i (the image distance) is 57.6061 metres.
So the change in focus is about 6 mm.

And they would have allowed for that variation when they built it-
Why wouldn't they?
It's not hard.
They would, of course, have to allow some focussing anyway because the focal length of the mirror (ironically) may not have been that precise.
They also needed to be able to change the focus because of requirements of different instruments within the 'scope.

So, if, as you seem to think, it was as simple focus error, they would have ben able to focus it.
No need for all the problems and embarrassment.


In particular if, as you seem to think, they wanted to be able to focus on the kremlin (it's pointless but never mind) and also on the stars, they would certainly have been able to do the same calculation I just did.


So, why are you saying they built the worlds biggest spy satellite,  disguised it as a science project (why?, by the way, the US military budget is so big that paying for Hubble wouldn't be a problem. Why not just be honest about it being a spy camera?) but they forgot that they would need to change focus?

Why do you think they were that stupid?

Your whole idea makes no sense.
If they wanted to spend that much to look at the Kremlin, they could have done a much better job- for a start you would choose a lower orbit. (or just bought a postcard.)
They didn't need to "disguise" it, they could have just kept it secret.

The distance from the Hubbles orbit to Earth is not infinity when referencing telescopes that are typically set up to view infinity as one would have when viewing the universe.  This is why the mirror was flawed, it's a fact as it happened because when the spy satellite disguised as a telescope was launched it WAS NOT A FUNCTIONING TELESCOPE.  Not sure why anyone would argue this as nothing that the government produces is what it says it is, remember when Hughes was mining manganese and really lifting a Soviet sub? Actually giving this camera a dual use made it more functional in the long run, but it did take photos of the Earth, with the highest resolution ever I do believe.
Title: Re: Were spare versions of Hubble built?
Post by: alancalverd on 20/07/2021 00:13:38
There are plenty of purely military satellites out there. Everybody knows that. The strength of Hubble is its light-gathering capacity, not its spatial resolution. If you want to spy on anyone on earth you really need a stereo camera in low orbit, and there's plenty of ambient light. And if you want to modify a military satellite, you don't publish your calculations, use a civilian crew, and do it on live public television.

Anyway, consider this as a warning: unsupported conspiracy theories are not really welcome here.
Title: Re: Were spare versions of Hubble built?
Post by: Just thinking on 20/07/2021 00:23:57
The distance from the Hubbles orbit to Earth is not infinity when referencing telescopes that are typically set up to view infinity as one would have when viewing the universe.  This is why the mirror was flawed, it's a fact as it happened because when the spy satellite disguised as a telescope was launched it WAS NOT A FUNCTIONING TELESCOPE.  Not sure why anyone would argue this as nothing that the government produces is what it says it is, remember when Hughes was mining manganese and really lifting a Soviet sub? Actually giving this camera a dual use made it more functional in the long run, but it did take photos of the Earth, with the highest resolution ever I do believe.
You have no understanding of optics the Hubble's primary mirror is about 8 feet in diameter a mirror of this size has a point of infinity of around 300 kilometres that means that if it is in focus on an object as close as 300 kilometres it needs no more in focus for objects at a further distance than that and the Hubble telescope was focused to look into infinity and it could look at the earth as the earth is further away than 300 kilometres but they don't waste time looking at the earth with the Hubble telescope as it was placed in orbit to study the universe. If the Hubble telescope was to focus on an object say 1 kilometre away it would have to move its camera /detector out of the craft so don't be silly and talk about a simple optical function that even your little telescope you have at home has. You know the focus tube moving in and out.
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 20/07/2021 00:44:40
The distance from the Hubbles orbit to Earth is not infinity when referencing telescopes that are typically set up to view infinity as one would have when viewing the universe.  This is why the mirror was flawed, it's a fact as it happened because when the spy satellite disguised as a telescope was launched it WAS NOT A FUNCTIONING TELESCOPE.  Not sure why anyone would argue this as nothing that the government produces is what it says it is, remember when Hughes was mining manganese and really lifting a Soviet sub? Actually giving this camera a dual use made it more functional in the long run, but it did take photos of the Earth, with the highest resolution ever I do believe.
You have no understanding of optics the Hubble's primary mirror is about 8 feet in diameter a mirror of this size has a point of infinity of around 300 kilometres that means that if it is in focus on an object as close as 300 kilometres it needs no more in focus for objects at a further distance than that and the Hubble telescope was focused to look into infinity and it could look at the earth as the earth is further away than 300 kilometres but they don't waste time looking at the earth with the Hubble telescope as it was placed in orbit to study the universe. If the Hubble telescope was to focus on an object say 1 kilometre away it would have to move its camera /detector out of the craft so don't be silly and talk about a simple optical function that even your little telescope you have at home has. You know the focus tube moving in and out.

Well if the Hubble was placed in orbit to study the universe the knuckleheads doing the math really screwed up huh, because it could not focus on anything.  In actuality it was working perfectly when orbiting over the Kremlin.  So you seem to be in denial of what is really happening and or happened. 

Carry on, and do tell us again that the US government never lies about it's spy satellites.  LOL times infinity to the trillionth power.
Title: Re: Were spare versions of Hubble built?
Post by: Just thinking on 20/07/2021 00:58:25
Well if the Hubble was placed in orbit to study the universe the knuckleheads doing the math really screwed up huh, because it could not focus on anything.  In actuality it was working perfectly when orbiting over the Kremlin.  So you seem to be in denial of what is really happening and or happened.

Carry on, and do tell us again that the US government never lies about it's spy satellites.  LOL times infinity to the trillionth power.
The mirror was ground and polished incorrectly and it was a big embarrassment to the manufacturer but it was corrected on a later shuttle mission with small optics placed in front of the camera the problem was just like having bad eyesight so the telescope got corrective lenses.
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 20/07/2021 01:05:32
Well if the Hubble was placed in orbit to study the universe the knuckleheads doing the math really screwed up huh, because it could not focus on anything.  In actuality it was working perfectly when orbiting over the Kremlin.  So you seem to be in denial of what is really happening and or happened.

Carry on, and do tell us again that the US government never lies about it's spy satellites.  LOL times infinity to the trillionth power.
The mirror was ground and polished incorrectly and it was a big embarrassment to the manufacturer but it was corrected on a later shuttle mission with small optics placed in front of the camera the problem was just like having bad eyesight so the telescope got corrective lenses.
That is exactly what the public was told, in reality the mirror was ground to the perfect specs if the mirror was turned onto the Earth
Title: Re: Were spare versions of Hubble built?
Post by: Just thinking on 20/07/2021 01:42:11
That is exactly what the public was told, in reality the mirror was ground to the perfect specs if the mirror was turned onto the Earth
No the telescope is in perfect focus at 300 kilometres and the earth is 500 kilometres from the telescope any object passed 300 kilometres is in perfect focus for the hubble if it looked at an object at a distance of 200 kilometres when focused to infinity it would look a little out of focus but there is nothing to look at closer than infinity for the Hubble if you have a little telescope at home and focus it on an object 2 kilometres away it is now focused to infinity. Just try and you will see. A little 2.5-inch objective will be focused for infinity at a distance of 2 kilometres so at a distance of 4 kilometres the focus will be of axis by no more than 2.5 inches which is non desernabal.
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 20/07/2021 01:55:16
That is exactly what the public was told, in reality the mirror was ground to the perfect specs if the mirror was turned onto the Earth
No the telescope is in perfect focus at 300 kilometres and the earth is 500 kilometres from the telescope any object passed 300 kilometres is in perfect focus for the hubble if it looked at an object at a distance of 200 kilometres when focused to infinity it would look a little out of focus but there is nothing to look at closer than infinity for the Hubble if you have a little telescope at home and focus it on an object 2 kilometres away it is now focused to infinity. Just try and you will see. A little 2.5-inch objective will be focused for infinity at a distance of 2 kilometres so at a distance of 4 kilometres the focus will be of axis by no more than 2.5 inches which is non desernabal.
Again the Hubble mirror was screwed up as in not perfect.  You seem to be creating a new reality
Title: Re: Were spare versions of Hubble built?
Post by: Just thinking on 20/07/2021 02:11:01
Again the Hubble mirror was screwed up as in not perfect.  You seem to be creating a new reality
Yes it was screwed up and others have told you that and I'm telling you that the company that made the mirror for the Hubble had a problem with the equipment that is used to check the accuracy of the grinding of the mirror it was a big blunder but it was fixed in space by a second shuttle mission and it was for looking at the universe and it sent images back to earth 500 kilometres away of very distant galaxies among other astronomical things. It can not read newspapers on earth if it could it would be able to see astronaut footprints on the moon and it can not do that.
Title: Re: Were spare versions of Hubble built?
Post by: Colin2B on 20/07/2021 08:17:49
.......In actuality it was working perfectly when orbiting over the Kremlin.  So you seem to be in denial of what is really happening and or happened. 
You have been warned about publishing unsubstantiated conspiracy theories.
If you continue you will be banned.
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 20/07/2021 08:35:45
the knuckleheads doing the math really screwed up huh,
No. The engineers doing the polishing screwed up.
That is exactly what the public was told, in reality the mirror was ground to the perfect specs if the mirror was turned onto the Earth
The shape you need is the same whether you point it up or down.
The different object distance would be accommodated by moving the mirror in or out slightly (as I calculated, about 1/4 of an inch), just like when you focus a camera.
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 20/07/2021 08:37:08
Again the Hubble mirror was screwed up as in not perfect. 
The focus was fine, but the mirror had not been ground to a parabola.
Title: Re: Were spare versions of Hubble built?
Post by: Just thinking on 20/07/2021 15:14:37
Don't no about spare parts but the telescope is a fantastic thing. the distant galaxies that it has imaged are incredible the magnification of the Hubble is very powerful as it has a focal length of 190 feet that is an F21 the telescope is a Cassegrain reflector a folded optical system that is a compact version of Isaac newton's reflector design. the telescope is racing around the earth at 8 kilometres per second and is about 500 kilometres above us. I wish I had the Hubble telescope in my backyard.
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 20/07/2021 19:55:53
Again the Hubble mirror was screwed up as in not perfect. 
The focus was fine, but the mirror had not been ground to a parabola.

Actually because of the mirror flaw the software was not able to achieve a focus, at least that is what we were told.  I still say that the mirror was fine when pointed at the Kremlin which was the purpose.  But people like you think that blurry images of nebulas were important
Title: Re: Were spare versions of Hubble built?
Post by: Just thinking on 20/07/2021 20:02:00
Actually because of the mirror flaw the software was not able to achieve a focus, at least that is what we were told.  I still say that the mirror was fine when pointed at the Kremlin which was the purpose.  But people like you think that blurry images of nebulas were important
Can you explain how it is possible for the earth to be in focus but not the stars? Optics with misshapen lenses are no good at any distance.
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 20/07/2021 20:11:00
Again the Hubble mirror was screwed up as in not perfect. 
The focus was fine, but the mirror had not been ground to a parabola.

Actually because of the mirror flaw the software was not able to achieve a focus, at least that is what we were told.  I still say that the mirror was fine when pointed at the Kremlin which was the purpose.  But people like you think that blurry images of nebulas were important
Do you understand that focusing a  telescope is moving the mirror (or the eyepiece) back and to in order to accommodate different distances to the object you are looking at and that aberration is what you get when the mirror is not the right shape?

They are different problems.
On is easy to fix, you just focus the thing.
The other is more difficult- you need to replace the mirror or use a corrector plate.
This plate is not the equivalent of glasses for someone who is short (or long) sighted.
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 20/07/2021 20:12:05
I still say that the mirror was fine when pointed at the Kremlin which was the purpose.
You can buy a postcard of the Kremlin with a better picture than you could get from Hubble.
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 20/07/2021 20:12:16
Actually because of the mirror flaw the software was not able to achieve a focus, at least that is what we were told.  I still say that the mirror was fine when pointed at the Kremlin which was the purpose.  But people like you think that blurry images of nebulas were important
Can you explain how it is possible for the earth to be in focus but not the stars? Optics with misshapen lenses are no good at any distance.
Hubble was a camera the mirror was only one part, lenses and computer software and a CCD were all required for focus and image capture

Next
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 20/07/2021 20:15:36
I still say that the mirror was fine when pointed at the Kremlin which was the purpose.
You can buy a postcard of the Kremlin with a better picture than you could get from Hubble.
Quite possibly true as I have not seen the images, but those images were the entire purpose of Hubble.  That said why do you speculate that the images would be inferior to any other spy satellite of the era?

Nyuk Nyuk Nyuk

(https://i.ytimg.com/vi/95t6wkX5g2s/maxresdefault.jpg)
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 20/07/2021 20:19:45
why do you speculate that the images would be inferior to any other spy satellite of the era?
Because I understand basic common sense.
The spy satellites were near the earth; the Hubble telescope was far away.
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 20/07/2021 20:21:33
Actually because of the mirror flaw the software was not able to achieve a focus, at least that is what we were told.  I still say that the mirror was fine when pointed at the Kremlin which was the purpose.  But people like you think that blurry images of nebulas were important
Can you explain how it is possible for the earth to be in focus but not the stars? Optics with misshapen lenses are no good at any distance.
Hubble was a camera the mirror was only one part, lenses and computer software and a CCD were all required for focus and image capture

Next
No.
When you write "Next" like that you have to have answered the question, and you didn't
If it was broken, how did it work?
Title: Re: Were spare versions of Hubble built?
Post by: Just thinking on 20/07/2021 20:23:02
Hubble was a camera the mirror was only one part, lenses and computer software and a CCD were all required for focus and image capture

Next
Thats got nothing to do with your own argument about the primary mirror so you have just gone off on a tangent that makes no sense at all. So now we have a camera and maybe some smaller lenses that apparently will only perform on an object that is 500 kilometres away and nothing else. Strange.
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 20/07/2021 20:24:09
Actually because of the mirror flaw the software was not able to achieve a focus, at least that is what we were told.  I still say that the mirror was fine when pointed at the Kremlin which was the purpose.  But people like you think that blurry images of nebulas were important
Can you explain how it is possible for the earth to be in focus but not the stars? Optics with misshapen lenses are no good at any distance.
Hubble was a camera the mirror was only one part, lenses and computer software and a CCD were all required for focus and image capture

Next
No.
When you write "Next" like that you have to have answered the question, and you didn't
If it was broken, how did it work?

LOL exactly what are you hoping to achieve here, and why is this so important to you?

Next
Title: Re: Were spare versions of Hubble built?
Post by: Just thinking on 20/07/2021 20:34:14
LOL exactly what are you hoping to achieve here, and why is this so important to you?

Next
First thing who are you talking to and second even if it wasn't important to us it sure sound like it is to you.
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 20/07/2021 20:34:48
what are you hoping to achieve here, and why is this so important to you?
Science, because this is a science page.

Can you answer one simple question before you go?

If the US military wanted to build a damned great spy satellite, why would they bother to lie about it?
Much better to brag about it- to tell the Russians to be careful or we would post pictures of their bald patches or something.

Why pretend it was a telescope?
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 20/07/2021 20:38:29
what are you hoping to achieve here, and why is this so important to you?
Science, because this is a science page.

Can you answer one simple question before you go?

If the US military wanted to build a damned great spy satellite, why would they bother to lie about it?
Much better to brag about it- to tell the Russians to be careful or we would post pictures of their bald patches or something.

Why pretend it was a telescope?
Actually this is a just chat about anything page.

Please pay attention, Adderall may help
Title: Re: Were spare versions of Hubble built?
Post by: Just thinking on 20/07/2021 20:41:47
Please pay attention, Adderall may help
Do you have old water pipes at home or is there a possibility that you're getting heavy metal poisoning from somewhere else?
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 20/07/2021 20:47:01
Please pay attention, Adderall may help
You forgot to answer the question.
Please pay attention, Adderall may help explain your delusions.
or, of course, you might actually be old enough to call me "son"- in which case I will assume you are senile.
The point remains, Hubble was a telescope, and they buggered up grinding the mirror.

It could not have been a spy satellite.
It was in the wrong orbit- too high and moving too fast- too blurred.
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 20/07/2021 20:47:58
If the US military wanted to build a damned great spy satellite, why would they bother to lie about it?
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 20/07/2021 20:48:38
Please pay attention, Adderall may help
Do you have old water pipes at home or is there a possibility that you're getting heavy metal poisoning from somewhere else?
You have no answers or rebuttals, all you have are vein attempts at distraction
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 20/07/2021 20:49:47
If the US military wanted to build a damned great spy satellite, why would they bother to lie about it?
So that the Premier would not know to cover his mail?

Next
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 20/07/2021 20:53:27

So that the Premier would not know to cover his mail?
He probably doesn't read it outside...

You can not put a big satellite up there without the Russians knowing.
If you as just some ill-informed nobody on the web think it might be a spy camera than it's sensible to recognise that the Russians might think so too, and make sure they read the post in the office rather than the garden.

So...


If the US military wanted to build a damned great spy satellite, why would they bother to lie about it?

Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 20/07/2021 20:55:49
You have no answers or rebuttals, all you have are vein attempts at distraction
That's rate silly from someone like you who repeatedly fails to answer anything.

Is "vein attempts " another drug reference?
Title: Re: Were spare versions of Hubble built?
Post by: Just thinking on 20/07/2021 20:58:33
Please pay attention, Adderall may help
Can I try some reverse physiology on you. You appear to be quite intelligent and smart not to mention very whitey please don't go away. 
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 20/07/2021 21:59:35

So that the Premier would not know to cover his mail?
He probably doesn't read it outside...

You can not put a big satellite up there without the Russians knowing.
If you as just some ill-informed nobody on the web think it might be a spy camera than it's sensible to recognise that the Russians might think so too, and make sure they read the post in the office rather than the garden.

So...


If the US military wanted to build a damned great spy satellite, why would they bother to lie about it?

You are probably correct, but you still do not tell your enemy how your secret spy systems work.  Does your country work like that?  Are you sure.

Logic works, try it sometime
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 20/07/2021 22:53:19
Logic works, try it sometime
Why should I?
It's not as if you do.
You keep ignoring it.
Your still trying to insist that Hubble was a spy camera.
But it can't have been.
Logic proves that.
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 20/07/2021 22:57:07
you still do not tell your enemy how your secret spy systems work.
Do you mean, you don't give them high definition video  images of you installing it?

If there was any chance you were right then the Russians would have been looking very carefully at that video (and the others).

Your right about logic.
Logic tells you that satellite wasn't a secret.
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 20/07/2021 23:19:48
you still do not tell your enemy how your secret spy systems work.
Do you mean, you don't give them high definition video  images of you installing it?

If there was any chance you were right then the Russians would have been looking very carefully at that video (and the others).

Your right about logic.
Logic tells you that satellite wasn't a secret.

Actually open secrets and or one thing posing as another are quite common in espionage.

I presume you remember the glomar explorer's foray into manganese nodule mining on the seafloor that was actually project azorian

 https://www.smithsonianmag.com/history/during-cold-war-ci-secretly-plucked-soviet-submarine-ocean-floor-using-giant-claw-180972154/

LOL now tell us that Hughes was really seeking manganese

Wheeeeeeeeeeeeeeeeeeeeeey
Title: Re: Were spare versions of Hubble built?
Post by: evan_au on 20/07/2021 23:25:53
As I understand it, the Hubble chassis and mirror were leftovers from an obsolete US spy satellite program. Space programs always keep a model on the ground so they can debug problems experienced in orbit. When this reconnaissance program was superseded, the ground model also become surplus to needs - so they offered it to NASA.

I understand that a similar offer was made more recently to NASA, when the subsequent spy satellite ground model also became surplus to needs. However, NASA was more interested in infra-red to see the early universe, stellar nurseries and the center of our galaxy, and went with the James Webb space telescope design instead. James Webb is to be launched later this year, hopefully..(it is now too expensive to be abandoned!).

There was definitely a problem in grinding the Hubble mirror for its revised mission. Apparently, the military has equipment that could have measured the mirror to the required accuracy, but NASA, as a civilian body, was not permitted to make use of it.

See: https://en.wikipedia.org/wiki/KH-11_Kennen#Size_and_mass
https://www.washingtonpost.com/national/health-science/nasa-gets-military-spy-telescopes-for-astronomy/2012/06/04/gJQAsT6UDV_story.html 
Title: Re: Were spare versions of Hubble built?
Post by: Europa on 20/07/2021 23:36:03
As I understand it, the Hubble chassis and mirror were leftovers from an obsolete US spy satellite program. Space programs always keep a model on the ground so they can debug problems experienced in orbit. When this reconnaissance program was superseded, the ground model also become surplus to needs - so they offered it to NASA.

I understand that a similar offer was made more recently to NASA, when the subsequent spy satellite ground model also became surplus to needs. However, NASA was more interested in infra-red to see the early universe, stellar nurseries and the center of our galaxy, and went with the James Webb space telescope design instead. James Webb is to be launched later this year, hopefully..(it is now too expensive to be abandoned!).

There was definitely a problem in grinding the Hubble mirror for its revised mission. Apparently, the military has equipment that could have measured the mirror to the required accuracy, but NASA, as a civilian body, was not permitted to make use of it.

See: https://en.wikipedia.org/wiki/KH-11_Kennen#Size_and_mass
https://www.washingtonpost.com/national/health-science/nasa-gets-military-spy-telescopes-for-astronomy/2012/06/04/gJQAsT6UDV_story.html

Actually the American military does not make mirrors, in fact the American military really does not make anything, military contractors do the construction to military standards.  So the measuring and grinding has nothing to do with the military though they might set the parameters for what they want or need
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 21/07/2021 22:35:40
Actually the American military does not make mirrors,
You do realise that nobody had said they do, don't you?
Title: Re: Were spare versions of Hubble built?
Post by: Bored chemist on 21/07/2021 22:40:41
The Hubble mirror was the highest optic ever put in a spy satellite
Highest is a good description.
It was the furthest from earth.

Which is a really stupid place to put a spy satellite.
If you want to look at something you go near to it rather than far away from it.