Go Inside a Telescope Mirror Factory | To a Billionth of a Meter

Beneath the University of Arizona football stadium sits the Steward Observatory Mirror Lab. There, giant mirrors are meticulously shaped and polished, to be used in telescopes around the world that are helping unravel the mysteries of the universe. The time-consuming production process requires that each mirror's surface be polished down to a billionth of a meter.
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Go Inside a Telescope Mirror Factory | To a Billionth of a Meter
• Go Inside a Telescope ...
National Geographic
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[@mbox314]

It says something about a nation's priorities when the largest telescope mirrors are being built in a space under a football stadium parking lot.

[@lapisredux]

it says something about humanity's priorities.

[@tomcarter1198]

The first nuclear reactor was also built under the football stands at the University of Chicago. When you need a large amount of space on a college campus, sometimes you are limited in your choices.

[@caaarbz]

Imagine complaining and using technology that was developed for space like ur phone, power tools, electric car, computer chips, gps

[@jimfling2128]

Fantastic! When I was a teenager in LA, I skipped school to watch the 200 inch Palomar lens go thought our neighborhood on its way to Mt. Palomar. It was a big event. The largest Pyrex pour in history at the time. And it would be the largest telescope for many years. It was stored for years at Corning where it was made till after WW II it spent years cooling and being ground. The final grinding was at the telescope on the mountain. It was the scope that confirmed that the universe is expanding.

[@wino0000006]

"Accuracy in these mirrors is just as Hubble's" - well I'm not sure that is the good comparison...

[@MarsFKA]

I saw what you did/said there. The Hubble mirror is, of course, flawed, but the technology and ability to make a reflecting surface to the uttermost tolerances that the Hubble's mirror was supposed to have been made have always been there. It was just that, in the pre-Hubble days, such precision was pointless because of the interference from the thick, turbulent atmosphere that ground-based telescopes have to look up through. Now that large mirrors are being made to be used in telescopes with adaptive optics, Hubble accuracy is now normal. Incidentally, the Hubble back-up mirror, made by Eastman Kodak, is perfect. It was never used in any telescope, but is displayed in the National Air And Space Museum.

[@chadkent1241]

The mirror in the Hubble was incredibly smooth, but the problem was it was ground to the wrong radius.

[@MarsFKA]

@@chadkent1241 Hubble mirror story follows: NASA decided that the building of the Hubble Space Telescope primary mirror was so challenging and so crucial that a backup was needed. The main contract went to Perkin-Elmer in Danbury, Connecticut, now known as Hughes Danbury Optical Systems Inc. At NASA’s request, Perkin-Elmer let the contract for the backup mirror to Kodak Eastman in Rochester, New York. The mirrors were to be ground and polished to standards never before attempted - the ability to make such precision mirrors had always been there, but ground-based telescopes had not been made to such exacting tolerances because the interference from looking up through a thick, turbulent atmosphere made such precision superfluous. However, orbiting above the atmosphere, the Hubble was going to need the best mirror ever made. The Kodak mirror, using conventional grinding and polishing techniques, was finished on time and on budget, but the Perkin-Elmer mirror fell behind schedule and delayed the eventual launch of the telescope. With both mirrors completed, Perkin-Elmer, as the primary contractor, had the say over which would be used in the telescope and, naturally enough, they went with their own mirror. So the Hubble was launched and expectations were sky-high. The first out-of-focus images started coming back and everyone realised that there was something badly wrong. NASA and Perkin-Elmer carefully analysed every step in making the mirrors, from casting to final polishing and found that there had been an error in testing the shape of the mirror. Perkin-Elmer had two types of testing instruments, called null correctors, that focused a laser beam on to the surface of the mirror to show up any irregularities. The older instrument, the refractive null corrector, used lenses to focus the laser, while the other, the reflective null corrector, used mirrors. The two instruments showed different readings from the Hubble’s mirror, so Perkin-Elmer used only the newer reflective null corrector during the final stages of the polishing and that was the problem, right there. The investigation found that two of the mirrors inside the null corrector were too far apart by the thickness of a steel washer. That meant the laser beam was slightly out of focus when it shone on the Hubble’s mirror, but the engineers doing the polishing accepted its readings and shaped the mirror to match the laser. The final shape of the 2.4-metre mirror was out by half the thickness of a human hair - enough to completely blur the images it was gathering. The term is spherical aberration. Returning the telescope to Earth for repair was out of the question, as it had been made to be launched, but not recovered, so optical geniuses, having analysed the problem down to the last ten thousand decimal places - bit of an exaggeration there, but you get the idea - made a tiny, specially-shaped mirror to fit into the light path from the telescope into a new Wide Field Planetary Camera (WFPC2), which was fitted to the telescope during the first service mission in 1993. WFPC1 was removed and returned to Earth. The tiny, specially shaped mirror in WFPC2 worked and the rest is history. WFPC2 was replaced on the last service mission to the Hubble in 2009 and has been displayed in the Smithsonian National Air And Space Museum. The unused Kodak Eastman backup mirror for the Hubble is also displayed in the NASM. Experts say that its optical quality is actually superior to that of the Perkin-Elmer mirror. WFPC2 is hailed as the camera that saved the Hubble. I have seen it in the NASM and, looking at the tiny mirror sticking out of the end of the camera, I still find it incredible that so much depended on something so small.

[@wino0000006]

@@MarsFKA True - the field cap on the invar rod had a chipped off tiny piece of non reflective coating - so the focus point alligment was off for about 1,3 mm. But it is astonishing how they discarded the refractive test. And if I remember correctly they were even offered some help in checking if the mirrors shape was according to the design - but the company refused.

[@larryscott3982]

wino0000006 The really crazy thing is that they test the mirrors side by side and choose the best. They made a backup. Two contractors, two factories, same product. But they didn’t check one against the other. 1.5 mm is so crazy far out. The report reads like a Dumb and Dumber screen play. The adjusting screws ran out! That was red flag. But just ‘oh well, shim it.’

[@cogoid]

The title says "to a billionth of a meter." Jonathan Davis says at 1:10 "to a thousandth of an inch" (which is 25000 billionth of a meter.) The truth is somewhere in between. I do not know the specifications for these mirrors, but precision optical surfaces are usually ground accurate to 1/10-1/20 of the wavelength of light. For the visible light, the wavelength is about 400-700 billionth of a meter, so the surface must be shaped correctly to 20-40 billionth of a meter -- about a millionth of an inch.

[@guillermomarturetfendt9037]

That's why you use metric, you would realise your error in seconds... Oh well, that's what you get I guess

[@irfanbinnoch]

ĶKOOJgyg8uiop , ... ?jki

[@Theothercrappyname]

The "thousandth of an inch" refers to grinding the overall shape of the mirror, the "billionth of a meter" title refers to the next process of polishing/figuring *surface peaks+valleys* down to as you say something like 1/10th or 1/20th wave which deals in nanometers (billionths of a meter) _or at least tens of nanometers_.

[@Aubstract]

I read an article about the Gian Magellan Telescope which said this lab polished its mirrors to 20 nanometers, I’m assuming that’s P-V. On Wikipedia (which it has a source for this) it says it will observe in wavelengths 320-25,000 nm, so for the shortest wavelength it has a P-V of 1/16 wave, and for the longest it has a P-V of 1/1,250 waves (insane!). But that’s one advantage of using longer wavelengths, the tolerances for the optical surfaces are wider.

[@Theothercrappyname]

​@@Aubstract That's right it's Peaks + Valleys, however the 20nm polish and the 320nm-25µm aren't really related at all. The 320nm-25µm number would be the wavelengths observed when using the completed telescope through cameras or whatever the observing equipment. The 20nm is the difference between highest peaks and lowest valleys of the mirrors shape, and the '1/X wave' is taken from the light's wavelength of the laser used in the interferometer used to measure this flatness. I can't for the life of me find what wavelength their laser was online, the most commonly used lasers in polishing/figuring are Helium-Neon lasers at 633nm, so when you hear "1/10th wave", it is generally 1/10th of 633 = 63 nanometers / or 633 divided by 20. If we assume they are using this common laser, we can go backwards and go 633/20 =1/30th wave, which is an extraordinary achievement for something so massive. Manufacturers will specify the Lambda fraction along with the wavelength of the laser used, so you'll see "1/10th wave @633nm" on technical drawings, or maybe "Better than 1/8th wave @543nm" required. And when you see λ Lambda from half life, you can take for granted it just means 1 - λ/10 is 1/10th, λ/40 is 1/40th etc. totally interchangeable really. Hope this makes sense, I could be getting totally mixed up rn because it's late. Essentially in polishing when we say 1/20 wave, we mean the peak-to-valley is 1 twentieth the size of the wavelength of the laser used in the interferometer measuring these numbers. 320nm - 25,000nm however is what the cameras will be looking at when the telescope is done and looking at the stars.

[@oliver3476]

I think this is so fascinating because it's literally a way to look back into time! The further the telescope can see into space the further you look back into the history of space 🛰🔭🌌

[@Imustfly]

"the accuracy of these mirrors is just like Hubble" In my head I was thinking, holy sh*t,...their building a near sighted telescope on purpose? ;-)

[@bmay8818]

The Mayall 4m Telescope was named after my grandfather, who was the director of Kitt Peak, among other things. At Kitt Peak they have a sample cross section of the mirror and I remember being amazed by how hugely thick it was. Then I read about the grinding of such mirrors and my mind was further blown. It's pretty impressive that they're still making huge mirrors!

[@singhnagra1540]

I want to own one of these...... Great

[@demej00]

Very cool grandfather! Have been to Kitt Peak several times on my motorcycle in the 90s. Loved to wander around the observatories.

[@bmay8818]

@@demej00 There is a lot of sciencing going on there! Years ago, the director gave me a long tour of the place. It was interesting to see how the Mayall, built in the 70s, had a single very large and heavy mirror, but their newest telescope, built in the 2000s,had dozens of very small ones mounted on actuators. Instead of relying on a huge chunk of quartz for thermal/image stability, the newer 'scope changes the shape of the mirror by moving its individual segments. Now that I'm married with kids, I really want to go back to Kitt Peak and get another tour!

[@stevec6965]

i think we owe honey bees a debt of gratitude for showing us the way to make a very strong rigid design that has been used in a lot of things we build.

[@slycooper5291]

You're right send them 2million pounds of honey right now.

[@yashsvidixit7169]

@@slycooper5291 that's not gonna cut it

[@TerryUniGeezerPeterson]

"We can't go to the universe.." We ARE IN the universe!

[@ausman05]

But we cant go to the places in the universe these mirrors can see.

[@ferrismesser]

I like the fact that dude was just walking over it in his socks

[@yatesyprenton74]

just hope we find life out there in my lifetime,,,,

[@albertgerard4639]

nope

[@tropicalfruitful1105]

Albert Gérard there might be life on Europa

[@sqwearl1392]

LOL. Title says one billionth of a meter... Video says .001 thousandth.

[@cnknguyen]

do you have a full length technical documentary on this place?

[@aerodicus]

My first thoughts after it ended.

[@Tadesan]

There are almost no actually technical documentaries of this type unfortunately.

[@ademirbelineli3433]

cnknguyen bainha fusao

[@snicker576]

No

[@piffi9431]

"we can't go to the universe, it's too far away"

[@lovemetender9979]

exactly what I thought... that guy talk stupid for an astronomer.

[@Mucho-Taco]

"We cant go to the universe, its just to big" 😑😳 you're in the universe.

[@labadjuju]

amazing, both the technology and all the people involved

[@Xiaotian_Guan]

At 2:02, there seems to be two curves on a single mirror? Isn't that the primary mirror for the Large Synoptic Survey Telescope instead of the GMT?

[@MrWeedWacky]

"we can't go to the universe" oooook???? I thought we were allways in the Universe, but then, where are we? :D

[@IARRCSim]

+MrWeedWacky I don't know about you but I work at a place called Next Dimension(nextdimensioninc.com/). That's where I spend a lot of my time.

[@EebstertheGreat]

+MrWeedWacky Maybe you're in the universe but that guy is really far away from it and observing it with telescopes. I bet he's jealous of your real estate in the universe.

[@MrWeedWacky]

EebstertheGreat then where is that telescope, if not in the universe?

[@EebstertheGreat]

MrWeedWacky Next door to the universe.

[@danielchais4603]

When I look at my back scratcher, I am seeing a part of the Milky Way. Is that an accurate statement?

[@iamnothere8557]

it is so fascinating. i wanna learn more about it

[@Midniteattack]

So if they make a documentary about mirrors, you'd think the cameraman would have thought about their reflection at 3:19 lol

[@danielchais4603]

Possibly it's a vanity issue.... Something to reflect on.

[@thePronto]

They're polishing this thing to a fraction of the wavelength of light, but some guy is walking on it in his socks. If he slips and falls face down, he is going to gouge the mirror with his belt buckle.

[@MariaGarcia281]

All in the name of science and our continued quest for answers ;-)

[@tubedude54]

I ground and polished 2 telescope mirrors when I was in my teen years... like 45 yrs ago lol. It was fun, educational and a lot of hard work! The first was a 6" mirror which was basically a learning tool and turned out very good. The next one was a 12.5" mirror and that one took some elbow grease lol and a LOT more time than the 6 did. It also turned out very well. Both still function but have pretty much given way to my Celestron 'goto' scope. I saw more objects in the first month I had the Celestron than in 30 yrs of using the other 2! Now that I'm retired I have been thinking of an 18" or 24" scope... let's see... new car or new scope??? Oh wait... I still have a wife! Guess it will be the car... unless.. I don't want a wife ne more...hmmmmm... what to do!?

[@Graeme_Lastname]

Can you cook? If you can then of what use is a wife? ;-)

[@joseluisrodriguez5302]

Telescope! car ? nahhh, wife ? unless she helps you carrying the scope....

[@Graeme_Lastname]

Get a telescope. It won't lie to you, it won't steal your money, it won't tell you what to do, it won't have kids .... Oh wait a tick, it will. :)

[@OpenGL4ever]

Get a computer and a large flat panel display with a high resolution and download the images of the big telescopes from the Internet. That's much cheaper and better. Save your money and use it for the new car.

[@dank9033]

keep the wife, astronomy is your hobby for life, right? easier and cheaper to buy a new scope, rather than make one from scratch like you did twice already, with poor results. luv your humorous question, but you already know what to do. your wife and you worked because you have a hobby that does not threaten her, keep both and die happy.

[@tobiaspiechowiak5432]

0:35 Not true! Schott in Mainz is just manufacturing the segments for the Extremely Large Telescope! I am always wondering if this is just mindlessness or if this is purpose to promote oneselves?

[@gustavpettersson9829]

Each segment of the ELT is less than 2m in size, so in terms of single mirrors that's not really comparable. However, way back in the 90s the 8m VLT mirrors were made also in Germany with spincasting (as they do in this video). I'm not sure if that production line is still available, pretty much everyone has moved on to segmented mirrors apart from the GMT. So the statement may actually be true (because no one else can be bothered anymore).

[@marcteenhc9793]

Purpose

[@bigboi5544]

"the accuracy is just like hubble" uh didn't they get they mirror wrong?

[@thurgogopro5338]

Only a billionth of a mtr, in Yorkshire it has to be spot on :)

[@Rejeckted]

I wish this was longer

[@aliensoup2420]

Why use glass for a mirror? A mirror needs a reflective coating, so you could shape and polish any solid material, then coat it. Glass is for refractive elements.

[@carlsaganlives4141]

The reversing,rotating head. Try building THAT in your garage.

[@ph11p3540]

I would love to see the specialized heavy moving trucks, cranes and ships that can move these mirrors anywhere in the world. Now those kind of moves are amazing to look at and watch. Even more amazing is watching a PTC super crane move a 2000 ton telescope training gimbal into position on it's plinth ring foundation.

[@ediposantos6574]

Someone can please explain why the mirror has two segments? the inner portion looks like having a very shorten focal lenght in comparison to the outsido portion, why this mirror has two different curvatures?

[@ediposantos6574]

Found: " It is a single mirror with two focal lengths. It acts as the primary and the tertiary mirror for the Large Synoptic Survey Telescope (LSST). As you can see, the mirror is ground to two separate shapes, the inner “circle” is the tertiary mirror and the outer “ring” is the primary mirror, when the telescope is completed, there will be a secondary mirror and detector positioned above this mirror." parallax.sci.cpp.edu/wordpress/?p=443 This allows a enormous field of view without distortions

[@McGyver777ATGMAIL]

The greatest things mankind can do is found in understanding our place within the cosmos without ego.

[@sbiegs3885]

You can see your soul if you look into these mirrors.

[@thePronto]

You could certainly see Uranus.

[@Anamnesia]

* I'm not sure stating your mirror to the "Accuracy of Hubble" is such a wise comparison. Wasn't the Hubble main collector ground incorrectly??? 🤔

[@stargazer7644]

Anamnesia, It was ground very, very, very precisely wrong. And Samuel, they did check it with another test rig, and it showed the mirror was incorrect, but they didn't believe the test results.

[@MarsFKA]

NASA decided that the building of the Hubble Space Telescope primary mirror was so challenging and so crucial that a backup was needed. The main contract went to Perkin-Elmer in Danbury, Connecticut, now known as Hughes Danbury Optical Systems Inc. At NASA’s request, Perkin-Elmer let the contract for the backup mirror to Kodak Eastman in Rochester, New York. The mirrors were to be ground and polished to standards never before attempted - the ability to make such precision mirrors had always been there, but ground-based telescopes had not been made to such exacting tolerances because the interference from looking up through a thick, turbulent atmosphere made such precision superfluous. However, orbiting above the atmosphere, the Hubble was going to need the best mirror ever made. The Kodak mirror, using conventional grinding and polishing techniques, was finished on time and on budget, but the Perkin-Elmer mirror fell behind schedule and delayed the eventual launch of the telescope. With both mirrors completed, Perkin-Elmer, as the primary contractor, had the say over which would be used in the telescope and, naturally enough, they went with their own mirror. So the Hubble was launched and expectations were sky-high. The first out-of-focus images started coming back and everyone realised that there was something badly wrong. NASA and Perkin-Elmer carefully analysed every step in making the mirrors, from casting to final polishing and found that there had been an error in testing the shape of the mirror. Perkin-Elmer had two types of testing instruments, called null correctors, that focused a laser beam on to the surface of the mirror to show up any irregularities. The older instrument, the refractive null corrector, used lenses to focus the laser, while the other, the reflective null corrector, used mirrors. The two instruments showed different readings from the Hubble’s mirror, so Perkin-Elmer used only the newer reflective null corrector during the final stages of the polishing and that was the problem, right there. The investigation found that two of the mirrors inside the null corrector were too far apart by the thickness of a steel washer. That meant the laser beam was slightly out of focus when it shone on the Hubble’s mirror, but the engineers doing the polishing accepted its readings and shaped the mirror to match the laser. The final shape of the 2.4-metre mirror was out by half the thickness of a human hair - enough to completely blur the images it was gathering. The term is spherical aberration. Returning the telescope to Earth for repair was out of the question, as it had been made to be launched, but not recovered, so optical geniuses, having analysed the problem down to the last ten thousand decimal places - bit of an exaggeration there, but you get the idea - made a tiny, specially-shaped mirror to fit into the light path from the telescope into a new Wide Field Planetary Camera (WFPC2), which was fitted to the telescope during the first service mission in 1993. WFPC1 was removed and returned to Earth. The tiny, specially shaped mirror in WFPC2 worked and the rest is history. WFPC2 was replaced on the last service mission to the Hubble in 2009 and has been displayed in the Smithsonian National Air And Space Museum. The unused Kodak Eastman backup mirror for the Hubble is also displayed in the NASM. Experts say that its optical quality is actually superior to that of the Perkin-Elmer mirror. WFPC2 is hailed as the camera that saved the Hubble. I have seen it in the NASM and, looking at the tiny mirror sticking out of the end of the camera, I still find it incredible that so much depended on something so small.

[@tobiaspiechowiak5432]

Not true. Schott Mainz has still the expertise to make these huge mirrors. But I think they are good in making the Keck type mirrors, so

[@SP-ny1fk]

Imagine if you could get this into space - the things it could see.

[@mauricio67589]

Espectacular, impresionante..!!!

[@ayatotakema1194]

i thought it was a pico or femtometer but its only a nanometer which is still preeatty impressive

[@xovAvox]

so sad that advancements like this arent at least a higher priority to our governments

[@giorgosgalanos9888]

"To a Billionth of a Meter" and yet they managed to mess up the Hubble space telescope's optics... about one millionth of a meter.

[@Raptorman0909]

How do they deal with the vibration caused by 25,000 fans cheering during a football game?

[@Raptorman0909]

Ouch ...

[@ExploringCabinsandMines]

joeylawn36111 haha good one.

[@ExploringCabinsandMines]

Raptorman0909 they might shut it down .

[@Automedon2]

It's not football season all year

[@halidharis]

So clever invention of this mirror and its purpose..but still flat earther in this giant sphere

[@SUPERPROJCC]

Dizem que a lente do Hubble diminuiu/ cedeu 3 mm de tanto polirem. O que muita coisa julgando pelo tamanho dele.

[@11thHrPro]

I could not imagine what this telescope is going to see. I have the suspicion that it's going to change the lives of many that observe through it.

[@StagnantMizu]

The HSC(8.2m mirror) serveys are mapping a good portion of the night sky you can import it into Stellarium, I think I discovered a high proper motion star by comparing that servey with the old sloan serveys which is insanely cool imo.

[@AI7KTD]

"We can't go to the universe" -- where do you think you live?!

[@machy8515]

I was about to write this XD

[@JoseSilveira-newhandleforYT]

You have to admit that many people don't really live here - they are stuck in fantasy worlds and refuse to face reality, no matter what - watching MSM shows that every day, and they seem to be growing in numbers.

[@cyrk75]

For some reason I find spamming 1 amusing !

[@fjoa123]

"acid ass"

[@waggerinator]

I always thought these mirrors are made to be so perfect as possible to eliminate distortion of the image these things will gather and then there is a person running around on this precisely made tool.

[@robertpaulsin6109]

Wish i understood how it actualy works.

[@richardcasaus3540]

"SOOOOO.. THATS HOW THEY MAKE MY EYE GLASSES"!?!?? 👍

[@AVERYhornyMrDinosaur]

honeycomb structures big! yeah yeah yeah! there not small? no no no!

[@TheIrishmanCan]

CLI Astronomy class brought me here

[@khaliffoster3777]

No closed caption so can add one.

[@jimzeleny7213]

I always wondered why they didn't just point it at a streetlight to see how it was working. If they had, they might have found the flaw before they launched the telescope.

[@richardl1743]

My exact thoughts!

[@zaha4193]

Imagine if that thing Breaks

[@thedegenerate9573]

If you can only hold a thousandth, you need a little help. I thought mirrors were super precise. Most of our guys in the tubing industry can hold three ten thousandths all day long on forty-year-old mills. That really surprises me, must mean across the entire radius. If the fuel rail in your car was off by a thousandth you'd have problems.

[@szaki]

LOL! Here they hold millionth of an inch , they measure things in light waves! Blue light has a wavelength of 450-495 nm (nanometers or billionths of a meter). It falls in the higher frequency of the visible light spectrum.

[@lordbyron3603]

How can something, in comparison to the universe, so tiny able to see far distances? It’s similar to a grain of sand in your living room with beings living within it and those beings making a mirror to see things in that room. It seems almost impossible. Perhaps it is ... and what we’re perceiving is an illusion.

[@mr.boomguy]

More like, a grane of sand in a cathedral.

[@KatzTheGnome]

This will be the next big thing Can`t wait :D

[@runningdebate2670]

That should be done by hand!

[@peachtrees27]

Interesting that a university became the go-to mass producer of insanely big mirrors. Is there no other company/entity producing ginormous mirrors these days?

[@brandonfrancey5592]

To what demand? Only a handful of telescopes on that scale are built every year. Cheap import mirrors are good enough for the rest of our needs.

[@11thHrPro]

Brandon Francey I concur. The cost at which creating a mirror this size has to be astronomical. It would not be profitable for any company to create mirrors of this depth on such a high scale.

[@boi2153]

Mmmmmmm a giant Glass Honey Comb

[@joelmathew616]

this is more of a circle than hexagon .Do you cut it ???

[@arturaskarbocius6091]

First navigation telescopes monocular called spyglass who konws maybe U2 planes used same technology for photocameras.

[@jbtechcon7434]

Why do mirrors have to be glass? Why can't you put the reflective material on something sturdier or lighter?

[@szaki]

Thermal expansion!!!!

[@jackbelk8527]

Glass is very strong and stable. These glass mirrors are plated for the reflective surfaces and can be stripped and replated many times.

[@anthonythomas1735]

I hope its more accurate than the Hubble space telescope, I'm pretty sure I'm right when I say that the first images were blurry due to a manufacturing mistake and had to be repaired/adjusted. Having said that when they got it right the images were amazing.

[@jamesrobinson949]

Anthony Thomas correct

[@cjr191]

The Hubble was very precise - they got the focal length very precisely wrong. After the correction for 'nearsightedness' (or 'farsightedness', I forget which), the Hubble has been doing science for a quarter of a century. Its near earth location allowed for 4 repair/upgrade missions, something that won't be possible with the Webb. I hope that get that one right from the get-go. Even before the first repair mission to fix the focal length issue, using some fancy signal processing, they were able to process and refocus some of the Hubble data based on the known problem. A null gravity check would have been required to simulate on orbit accuracy, as earth-bound, gravity pulls it out shape.

[@stargazer7644]

@@cjr191 They mirror wasn't nearsighted or farsighted. It had spherical aberration. The center of the mirror and the edge of the mirror had very slightly different focal lengths.

[@facade7672]

3:01 pretty sure you mean inspiration,bud...

[@jozefbania]

Look to the stars.

[@zoesdada8923]

It's still hard for me to grasp or remember that space and the universe is a natural thing. Its the wilderness. The wild frontier.

[@mr.boomguy]

Ikr. The universe created itself. No unnatrual forces at stake, just pure physics.

[@SmeeUncleJoe]

A stickler for details I am.... "Seven times thinner than a human hair" = 1 thousandth of an inch ??? Not quite. Get that micrometer out. A human hair measures between 2 and 3 thousandths.

[@cawsomepeople1234567]

Cool

[@stevedoe1630]

Philosophically, what if we (Earthlings) confirm that we are the only ones that exist in the universe? What would that mean? Are we special? Are we alone? Are we “prepared” to deal with that contingency?

[@stargazer7644]

We can't, and we aren't.

[@pattrixsquidword6739]

the thumbnail looks like a big one egg

[@billlawson5571]

Obviously money is everything how could you do the whole thing, without any detail, on something this unique?

[@mussemulugetadejene3740]

I'm asking if there is a software that ahelp of eye glass and hearing aids can see and lissen sound of Jesus(angeles) and deviles(damianes) or a video camera software that both appeared?

[@Thanatos4655]

We are in the universe

[@irishman1681]

Am I the only one who noticed the honeycomb pattern inside the big mirror is a pentagram.

[@passaroquetemasanaovoa]

patrick murphy yes

[@rebanse8891]

Japan can do in 7 days or less lol

[@ManishKumar-pp6tu]

👍👍

[@pattycollins8022]

nice

[@the3rdid485]

00:35.....he sounds like the milkman from South Park

[@danielchais4603]

How much will that mirror cost? It's larger than the Hubbard.... Will that more than compensate for it being in the Earth's atmosphere?

[@keet111]

You mean hubble? Also the size of the mirror can compensate for the earth's atmosphere only to an extent, this is what adaptive optics is for. Also the mounts of most telescopes allow it to counteract the earth's rotation, the only real advantage of the hubble is that the atmosphere doesn't interfere with its optics.

[@danielchais4603]

David W In my hubble opinion, your reply is right on.

[@kevino3866]

Amazing on how illiterate people are when it comes to spelling! It is Hubble, not "humble" or "Hubbard" etc.

[@stargazer7644]

No, actually making the mirror bigger makes it worse when used in the Earth's atmosphere. You have to use adaptive optics on the secondary mirror to correct for the unstable atmosphere and get full use of a mirror this size.

[@akupehsluarketatAR]

my wife's make up mirror

[@jeremytheimer7443]

151 they want the mirror to be super precise yet they have someone walking on it.

[@TechKidShazil]

Its probably a blank

[@jimbojet8728]

Don’t Americans know that one fourth, is a quarter ?

[@SuperGonzales94]

Old Michael?

[@lawrenceshuda]

W.O.W.

[@MrArturhM]

He struggled to answer about the purpose of the lens same as those who plan to travel to the moon or mars.

[@Mr30friends]

what

[@MrArturhM]

@@Mr30friends There are tons of imagery about travels to outer space and finding intelligence or finding life or something else but after billions spent on space exploration the concrete benefits for the regular inhabitant of this planet are cero, I think It’s time to slow down and take a better look at what we have here: UNICEF reports that in 2018 every five seconds a child died mostly from preventable causes, of course that suffering occurs far away from our homes and lives but much, much closer than that of which this scientist vaguely refers as: “you know? The multiplicity of things that are out there, the weird stuff, the grand vistas, everything”

[@Mr30friends]

@@MrArturhM "the concrete benefits for the regular inhabitant of this planet are zero", writes Arturo from his computer... ahahhahahahahaha, the irony is staggering.

[@TechKidShazil]

Curiosity

[@dominic6634]

Worked at an optics place got to make a lot of stuff for satillites

[@Hope4Today9]

This video told me next to nothing.

[@JohnCThomas24]

Anyone else catch him saying a human hair is .007? He must have some thick hair

[@shashidhar1248]

He said 7 times thinner than human hair

[@JohnCThomas24]

@@shashidhar1248 correct implying one thousandth of an inch is 7 times thinner so a human hair is .007 in diameter

[@cogoid]

@@JohnCThomas24 His whole speech 1:10 is inaccurate. Maybe the first rough diamond machining is done to a thousandth of an inch, but the goal in actual grinding of such a mirror is usually to make it parabolic to within about 1/20 of a wavelength of light -- the surface is accurate to *a millionth of an inch* not a thousandth. Even the title of the video says "To a Billionth of a Meter" (in reality it is a few tens of a billionth, but that is still way better than a thousandth of an inch.)

[@Robin-ic7sy]

don't drop it

[@yourface3154]

We can't go to the universe...... Umm, that was a terrible way of saying that...

[@peesweezy4553]

Spherical abhorration

[@MrShadow6292]

Much easier to smoke DMT then travel there in person.

[@eldstgilmorbarboydodellatb4413]

👍🏿🤘🏿🦑

[@denispol79]

Mirror accuracy just like Hubble... Khhm.. khhm..

[@jerrysg7]

The Hubble mirror was quite accurate; it was just accurately ground to the wrong focal length. That was corrected though.

[@denispol79]

@@jerrysg7 yeah, I know )

[@Jimbob84141]

Stick it on Elon musks rocket... Let's go!

[@dcn584]

neat! the earth is flat though so this is a complete waste of money

[@jackbelk8527]

How thick is it and what's on the other side?

[@administrator7400]

"we cant go to the universe" - only true thing said in this video. everything else was a wonderful sideshow smokescreen to placate us into giving more of our paychecks next week.

[@kevino3866]

Amazing on how illiterate people are when it comes to spelling! It is Hubble, not "humble" or "Hubbard" etc. Just read some comments and you will shake your head!

[@jeffvoight6586]

I suspect you don't have a tablet or, you'd be used to autocorrupt changing all manner of properly spelled words into so much nonsense.

[@davepastern]

yes, but that doesn't stop you from proof reading what you type and correcting it before hitting the submit button, does it?

[@ExploringCabinsandMines]

kevin O sometimes spell check iris not your friend. But hey thanks for being everyone's mom.

[@ml.2770]

Humblepie

[@gjg3783]

Maybe they have difficulty hearing?

[@GlobalTriathlonNetwork]

Science not using metric. U fools