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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
Quote from: syhprum on 17/07/2021 09:00:38The 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 spareActually 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
Quote from: Europa on 19/07/2021 16:04:16Quote from: syhprum on 17/07/2021 09:00:38The 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 spareActually 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 produceThat'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.
new computer programming was installed to correct for the flaw. You may or may not remember this, I do.
Look it up, it's all there.
Quote from: Europa on 19/07/2021 16:52:04 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,Quote from: Europa on 19/07/2021 16:52:04 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?
When launched the Hubble was only able to focus on the Earth
Quote from: Europa on 19/07/2021 16:52:04When launched the Hubble was only able to focus on the EarthNope. That's just wrong.
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 focusing on Earth was the purpose of the Hubble
the designers hoped that it would also function on the stars
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
Quote from: Europa on 19/07/2021 17:40:52The 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.Quote from: Europa on 19/07/2021 17:40:52 So focusing on Earth was the purpose of the HubbleIt could not do that.If you think it could, then prove it.Quote from: Europa on 19/07/2021 17:40:52the 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 KmSo 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?
It's there, you can search it on your own I presume
I remember what they actually did to fix the flaw.https://esahubble.org/about/general/instruments/costar/
The Hubble mirror was the highest optic ever put in a spy satellite, perhaps someday it's Earth photos will be declassified.
digital image capture was revolutionizing photography at this time
Quote from: Europa on 19/07/2021 18:01:26It's there, you can search it on your own I presumeI pointed it out to you.Quote from: Bored chemist on 19/07/2021 17:32:36I 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.
Quote from: Europa on 19/07/2021 18:08:23 digital image capture was revolutionizing photography at this timeYou 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.
I came up with nothing,
new computer programming was installed to correct for the flaw.
If you read you will see that nearsighted is mentioned
New optics do not require such large lenses
computer enhancements actually now do much of the focusing
Quote from: Europa on 19/07/2021 18:16:10I 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 thisQuote from: Europa on 19/07/2021 16:52:04new computer programming was installed to correct for the flaw. People are laughing at you.Quote from: Europa on 19/07/2021 18:16:10If you read you will see that nearsighted is mentionedYes.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 herehttps://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.Quote from: Europa on 19/07/2021 18:20:52 New optics do not require such large lenses They don't use lenses much.They use mirrors.Quote from: Europa on 19/07/2021 18:20:52computer 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.
They don't use lenses much.They use mirrors.