Cold War Spoils: Amateur Builds Telescope With 70-Inch Lens 101
First time accepted submitter 192_kbps writes "Mike Clements, a long-haul trucker from West Jordan, Utah, built the largest amateur telescope ever with a whopping 70 inch primary mirror he purchased at auction. The entire telescope is 35 feet tall, 900 pounds, and he hopes to tour it in parks. As a hand-turned Dobsonian the telescope lacks the photographic capacity and tracking required for professional astronomy but the views must be breathtaking." (Are there other compelling candidates out there for "largest amateur telescope ever"? The 71" scope listed by nitesky.org appears to be dormant.)
Did he buy the mirror, or make it? (Score:3)
This is unclear to me:
"One of the riskiest parts of the project was turning the huge 70-inch piece of glass into a mirror by applying the silvering himself."
vs.
"Clements bought the 900-pound mirror — which was originally destined to go into space as part of a spy satellite until the edge of it was chipped during its manufacture — after it was auctioned off."
Re:Did he buy the mirror, or make it? (Score:4, Informative)
He put a reflective metal coating on a purchased piece of glass with the proper final curvature.
Re:Did he buy the mirror, or make it? (Score:5, Interesting)
Alternatively, the intended use may have involved some classified exotic coating that serves some special purpose and they needed to strip the coating before selling the mirror at auction.
Re:Did he buy the mirror, or make it? (Score:5, Informative)
I read it the same way.
They probably cut the mirror and polished the glass, and then the edge chipped.
A chip in the glass could be a fatal injury for a spy satellite as the article suggests was the intended use. Such telescopes use active optics to improve image quality; they apply pressure over the glass to bend it slightly. A chip could have micro-cracks and other damage that would easily spread across the surface. Without the actuators deforming the glass the image won't be as clear, but it would be good enough for a hobby telescope.
Once the glass chipped they likely just stopped the process, so the new owner would need to add the mirror surface on his own.
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They talk about it over on cloudynights,
The crack goes about a foot into the glass. The spray on coating leaves much to be desired, it needs to be re-coated every so often and it has a fairly low reflection index for whats commonly used in telescope mirrors. But with that said its still a hell of a project and I'd love to use it!
Re:Did he buy the mirror, or make it? (Score:4, Interesting)
A chip in the glass could be a fatal injury for a spy satellite as the article suggests was the intended use. Such telescopes use active optics to improve image quality;
Why? It's in microgravity and temperature controlled. There's not going to be any sort of variation during operation to make active optics worthwhile. It's certainly not going to be adaptive optics, because you're moving across the atmosphere too rapidly to have any hope of keeping up with localized distortions. The only reason I could see it being useful is it would allow for more lax manufacturing tolerances, since you could fine tune it once you hit orbit.
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State of the art spy satellite require active optics because they look at things through the atmosphere. Not upward like a ground-based astronomy telescope, but downwards.
Re: Did he buy the mirror, or make it? (Score:2)
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Re:Did he buy the mirror, or make it? (Score:4, Informative)
Why? It's in microgravity and temperature controlled.
When you're in orbit, "temperature controlled" is a slippery concept. You've got direct sunlight on one side, dark space on the other side, temperatures to the fourth power fighting it out, and no air to redistribute heat -- and an hour later, the sides will have switched.
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A chip in the glass could be a fatal injury for a spy satellite as the article suggests was the intended use. Such telescopes use active optics to improve image quality; they apply pressure over the glass to bend it slightly. A chip could have micro-cracks and other damage that would easily spread across the surface. Without the actuators deforming the glass the image won't be as clear, but it would be good enough for a hobby telescope.
Once the glass chipped they likely just stopped the process, so the new owner would need to add the mirror surface on his own.
Not so. Firstly, adaptive optics is still fairly rare and likely this mirror was never intended for use in such a telescope. Secondly, the mirror deformations on a telescope with adaptive optics are not done at the primary mirror (the large chipped one) but at the secondary or even tertiary mirror. It's much easier to do this on a small, thin, mirror than large, thick one. Finally, a little chip is no big deal. You just coat the mirror as normal then paint over the chipped area. You'll never see the differ
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I don't know this for a fact but I am dubious that adaptive optics can or are used for telescopes looking down at earth. From my lay understand of adaptive optics, a "guide star" or artificial star (artificial spot in the sky lit up with a frickin laser!) is used to correct for the atmospheric disturbances. I am having a hard time thinking of what could be used as a point source when looking at the ground from space. Maybe a point light source near the area of interest?
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I'm a scientist working in adaptive optics. Reading this whole thread, in which essentially every statement made is untrue or imprecise, gives me some idea of what it must be like to be a climate scientist listening to constant babble from people trying to talk about a technical area outside their area of expertise. (No insult intended toward any commenters in this thread, I'm just sharing my epiphany.)
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I am having a hard time thinking of what could be used as a point source when looking at the ground from space. Maybe a point light source near the area of interest?
So just to be clear, you're having such a hard time figuring it out, that you just figured it out?
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Do things that you want to spy on have a convenient point source near them?
If they don't, you drop one. It's not as hard as you imagine when you have an effectively unlimited supply of taxpayer money.
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No, the main reason that AO is not used for atmospheric correction in satellite systems is the so-called "shower curtain" effect. The atmospheric aberration effect is strong for ground telescopes because the atmosphere is near the 'scope, and thus is in the region where the light's phase is important. Looking down from a satellite (analogous to looking from the far side of the room at a person just behind a shower curtain), the atmosphere is where the light's angle is important, not phase.
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Because it has a non-uniform thickness and therefore bends the light in addition to reflecting it.
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Because a mirror used in such a way is effectively a lens, even if it isn't one technically. Is the headline correct? No, but it's correct enough that you've got to be in a pedantic mood to bother complaining about it.
It's hardly pedantic to point out that a mirror is not a lens. Would you complain to your contractor if he accidentally installed a bathroom lens instead of a bathroom mirror? Or just let it slide since they are pretty much the same thing and only a pedant would complain?
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Would you complain to your contractor if he accidentally installed a bathroom lens instead of a bathroom mirror?
Depends on if it performs the function of letting me see a low-distortion image of myself or not.
Of course mirrors and lenses are different; the reason I posted is that I'm annoyed how many people thought they were being clever by pointing it out.
Re: Did he buy the mirror, or make it? (Score:2)
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Re:Did he buy the mirror, or make it? (Score:4, Informative)
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because a 70 inch reflector is interesting, but a 70 inch refractor is extraordinary. By not making the type of telescope clear in the headline, the submitter is practicing good click bait techniques. Not nearly as enticing as "Charlize Theron NSFW", but...
Re:Did he buy the mirror, or make it? (Score:5, Funny)
"Charlize Theron NSFW"
I keep clicking on those words, but nothing happens :(
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"Charlize Theron NSFW"
I keep clicking on those words, but nothing happens :(
.... that you KNOW about :)
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If you stick a 900 lb piece of glass on top of a rumbling shaking rocket and expose it to 5Gs of acceleration, rapid heating and cooling cycles etc, you probably don't want a chip in the glass where forces can propagate a crack. It's easier to make a new one rather than wait for it to fail in space.
For something that will only see occasional use with slow temperature changes it's ideal for a "low cost" telescope. It will still fail eventually, but it won't shatter in orbit while imaging a North Kore
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> it will still fail eventually
Not necessarily, if he took the time to de-stress the chip. It will still be a weak point but will not necessarily propagate.
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So... call up Safelite and they send a guy out to inject some goop in the glass?
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It was referred to as a chip, not a scratch. Just grind/polish it.
HST comparison, really? (Score:3)
According to TFA : enabling users to see constellations previously visible only through the $2.5 billion Hubble Space Telescope
Hahaha, but no...
Re:HST comparison, really? (Score:4, Interesting)
Riiight.. I mean the guy lives in Utah so there are dark skies close enough to him but I'm plagued with air pollution and light pollution in my area and have to go at least 3 hours away to get a decent night of observation. Even then you still have upper atmospheric interference at times whereas the HST doesn't have any of that. The other problem I'd see with a Dobsonian of this size is maneuvering it and hauling it without damaging it. Props too him though for building it though, I wonder how many times he had to go to Home Depot to finish it?
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I think the problem here might be the word 'constellation'.
And that they're claiming it outperforms any of the other terrestrial telescopes from 70.1 inches up to the 409 inch Gran Telescopio Canarias, and presumably any bigger ones still being built.
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Actually, west jordan is in the massive sprawl complex that stretches from North Ogden to Nephi. He would probably have at least a couple hours drive to get up past Park City, Heber, Payson, or out towards the west desert, Tooele, or even Dugway He will have some driving if he wants darkness. Utah'ns in general take a "consumptive model" view of nature, and aren't big into reducing pollution, let alone LIGHT pollution.
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Cool project, though.
Like HST (but not in a good way) (Score:2)
Remember how when it first went up, the hubble had problems focusing clearly? The designers forgot that its mirrors would be deformed/reshaped by the lack of gravity. Essentially, the hubble's primary mirror was optically designed to work as a telescope mirror on earth, not in space. It w
Re:Like HST (but not in a good way) (Score:4, Informative)
Remember how when it first went up, the hubble had problems focusing clearly? The designers forgot that its mirrors would be deformed/reshaped by the lack of gravity. Essentially, the hubble's primary mirror was optically designed to work as a telescope mirror on earth, not in space.
Uh, no. That would've been an amateur mistake to make and didn't happen.
Instead, the amateur mistake made was not to properly verify that the grinding
machine was actually grinding correctly. They even ignored measurments by
another instrument showing a faulty shape, assuming the instrument to be faulty instead.
And skipped the final post-assembly check to save time and money.
The mirror simply was ground extremely precisely into a wrong shape, and nobody noticed.
But as always in cases like this, the whole story is more complex and consists of a lot of
things not going as planned. It's a good and instructive read. [tamu.edu]
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Daily Mail is like National Inquirer (Score:4, Informative)
Just a heads up for you non-Brits. There will be truth in this article... somewhere.
Re:Daily Mail is like National Inquirer (Score:4, Insightful)
FYI over the last 10 years or so the 'National Inquirer' has done more genuine 'investigative reporting' then the New York Times.
They have the nerve to report stories that 'the powers that be' have put an embargo on.
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Then I stand corrected - it is much worse than the National Enquirer.
Re:Daily Mail is like National Inquirer (Score:4, Insightful)
Let's not get hyperbolic. As many problems as I have with the NYT, a couple of sex scandals involving politicians doesn't measure up to what the NYT does every day. Now, take a look at what the Enquirer reports on every day.
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Being the PR wing of the DNC is not a good thing.
Name one example of real investigative journalism from the NYTimes in the last 10 years?
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I won't matter what I reply with because you've already invoked the "real Scotsman" fallacy in your question. Anything posted won't count to you.
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I'll take that as a no.
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Yes, the National Inquirer may do more investigative reporting, but if no one believes it because 90% of what they report is false then who gives a fuck?
Largest Amateur telescope. (Score:4, Informative)
Technically Lord Rosse (https://en.wikipedia.org/wiki/William_Parsons,_3rd_Earl_of_Rosse) was an amateur, and his telescope was 72 inches.
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I think once you carry the Lord title you can never again be revered to as an amateur in anything.
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It's not as impressive as it sounds. The title is heretitary, so it basically means 'My ancestors were filthy stinking rich, and I probably am too.'
When we want to grant someone a title of respect, they get the 'Sir' before their name, not Lord. You have to earn that one personally, not just get born into it.
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This guy earned "Long Haul Trucker" and is building a telescope with money he works for.
I find that much more respectable than the right honorable lord sir fuckface pursuing hobbies with leisure time and leisure money.
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The lord didn't have a truck to haul the mirror.
No disrespect for the trucker (certainly not: Hats off), but doesn't give reading about Rosse's achievements on http://en.wikipedia.org/wiki/William_Parsons,_3rd_Earl_of_Rosse [wikipedia.org]
you cause to revise your statement at least somewhat?
Bert
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To the contrary, you can never be referred to as a professional. Having to work a job is for the little non Lord people.
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Lord Rosse's telescope used a cast speculum metal mirror [wikipedia.org], basically pewter, which had a reflectivity of 66%. Glass silvering technology had not been developed to a level adequate for astronomical mirrors. As a result the light gathering power of the 72" Leviathan of Parsontown was equivalent to a 58" mirror of 100% reflectivity. Clement's mirror is coated with silver, and with even a mediocre silvering job a reflectivity at least 90% should be obtained. This makes his mirror equivalent to a 66" mirror of 10
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William Parsons (Lord Rosse) cast and figured his mirrors with 1845 technology that he helped improve through his own efforts. It doesn't matter what the sensitivity or apparent size is in relation to a mirror created with 20th century technology developed by Lockheed with unknown millions in government funding. The Leviathan has a larger diameter mirror which is the criteria many news sources are using to claim that Mr. Clements's telescope is the largest ever built.
I'm saddened to see that this has turned
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Correction: Obviously 1845 was not over 200 years ago. I don't think this undermines the point, however.
Trust me (Score:2)
Or so I've heard.
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You really don't need a mirror this large to spy on your neighbor.
It depends on how large the neighbor is...
Isn't there even one picture through it? (Score:4, Insightful)
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I was wondering the same thing. Thought it might be a stability issue since the rig has no gears and it's moved by hand?
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Or you can build a rotating camera mount, or insert a rotating element in the optical path. Either way, you're supporting and moving a relatively small weight, so it's a much easier task than building the main drive.
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Re:Isn't there even one picture through it? (Score:5, Interesting)
Taking short exposures and processing them on a computer is the "poor man's adaptive optics". A very powerful technique (if the object is bright enough) is too take a large number (thousands) of short exposures, then sort through them for a "lucky" image - one in which the atmosphere is momentarily stable. Multiple lucky images can be stacked together to get longer exposures. This really is a very powerful technique, not requiring extremely expensive high precision tracking hardware.
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Bad Headline: Mirror Not a Lens (Score:5, Informative)
Here is the scoop on the 70" telescope. Mike Clements purchased a polished but uncoated mirror that is 70" across that was intended for a spy satellite project that was cancelled. A huge uncoated mirror is not a telescope anymore than (car analogy - wait for it...) a V8 engine is a racecar. Building a good performing telescope (collimation tolerances are measured in thousandths of an inch) is a significant task, a huge telescope like this is a major engineering feat. What's more this is a transportable telescope. It is possibly the biggest transportable telescope in the world. This telescope is more powerful than any telescope that existed before 1917 (when the 100" Hooker telescope saw first light).
Successfully silvering the mirror using updated 19th Cedntury mirror coating technology was nifty too.
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Here is the scoop on the 70" telescope. Mike Clements purchased a polished but uncoated mirror that is 70" across that was intended for a spy satellite project that was cancelled. A huge uncoated mirror is not a telescope anymore than (car analogy - wait for it...) a V8 engine is a racecar. Building a good performing telescope (collimation tolerances are measured in thousandths of an inch) is a significant task, a huge telescope like this is a major engineering feat. What's more this is a transportable telescope. It is possibly the biggest transportable telescope in the world. This telescope is more powerful than any telescope that existed before 1917 (when the 100" Hooker telescope saw first light).
Successfully silvering the mirror using updated 19th Cedntury mirror coating technology was nifty too.
From another site: Clements began began building a steel structure to house the mirror in 2012. He did it without formal training in telescope construction or welding and without any blueprints. "He's got nothing on paper," said Clements' friend, Steve Dodds. "He did make a model out of popsicle sticks." Clements finished the telescope and in late September, he said he put a reflective coating on the mirror with a weed sprayer. [ksl.com]
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You don't need to be a savant to overbuild a metal structure. Good for him that he apparently did so, though, and didn't underbuild it.
We used to build stuff ONLY by copying others, or by building stuff and then rebuilding it if it broke. We only iterate faster now, with fewer failures.
22" Mirror (Score:2)
I have a Dobsonian 22" Mirror that I built from scratch about 10 years ago.
A telescope is only as good as it's lenses. Normal lenses I call Coyote Lenses because they are so crappy that they are only good for throwing at coyotes during star parties.
Some further info... (Score:5, Informative)
Cloudy nights thread [cloudynights.com] and a another news article [ksl.com].
It was silvered with a spray-on solution using a weed sprayer; much too large for the regular vacuum deposition chambers.
-R C
Hats off to this man! And for once, the Eds.. (Score:5, Insightful)
Truely "news for Nerds". Brings back fond memories of building 'scope and staring at the skies with my father.
This man has drive, dedication and the ability to both conceptualise and physically realise his dreams.
Instead of bullshit "surveys" with no-longer-funny "CoboyNeal" options, here's a serious suggestion - how about we instigate the /. annual "Nerd" awards?
Fuck it, this is going way offtopic, but I don't care...categories anyone?
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Most nostalgic old guy crapping on new stuff in a Slashdot post.
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I know nothing of Astrology* and telescopes, but these stories spark imagination.
*I know what word I typed.
Pics (Score:3)
You don't really appreciate what an awesome amateur effort this is until you see pics http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/6146228/page/0/view/collapsed/sb/5/o/all/fpart/2/vc/1 [cloudynights.com]
Being the owner of an 8" Schmidt–Cassegrain scope, this blows my mind.
70- inch mirror, not "70 inch lens"! (Score:2)
Re:70- inch mirror, not "70 inch lens"! (Score:5, Insightful)
You might owe yourself another slap. It's a reflecting telescope. Grins.
Its soo good (Score:2)
he didnt bother to post any pictures captured with it. Only pictures of an ugly metal contraption.
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Dobsonian-style telescopes are generally not capable of proper astrophotography. Withouth significant work to put this thing on a barn-door-style tracking motor drive, as well as a setup that rotates the camera in the "eyepiece" holder to account for field rotation, this wont work well to capture images.
My big lens story (Score:4, Interesting)