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Cold War Spoils: Amateur Builds Telescope With 70-Inch Lens
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.)
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."
According to TFA : enabling users to see constellations previously visible only through the $2.5 billion Hubble Space Telescope
Hahaha, but no...
Just a heads up for you non-Brits. There will be truth in this article... somewhere.
Technically Lord Rosse (https://en.wikipedia.org/wiki/William_Parsons,_3rd_Earl_of_Rosse) was an amateur, and his telescope was 72 inches.
You really don't need a mirror this large to spy on your neighbor.
Or so I've heard.
They can take my LifeAlert pendant when they pry it from my cold dead fingers.
How hard is it to rig up a camera adapter? That'd help demonstrate exactly how powerful it is...
PHEM - party like it's 1997-2003!
It's a mirror, not a lens.
We always got to say ours are bigger!
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.
Second class citizen of the New Gilded Age
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.
"I think you know what I'm talkin' about, Mr. President; We're gonna kill us a mummy!" - Bruce Campbell as Elvis Presley
Cloudy nights thread and a another news article.
It was silvered with a spray-on solution using a weed sprayer; much too large for the regular vacuum deposition chambers.
-R C
"'Tis great confidence in a friend to tell him your faults, greater to tell him his." --Poor Richard's Almanac
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?
Just yesterday I saw this telescope tracker. You need your own motors/gears (actually you need to build the whole thing yourself). Its low cost, and all the plans and software is there. Looking at stars is nice, looking at stars from a warm room by way of a high-res computer monitor is even nicer. You could even look at stars by way of a web interface. Now *that* is remote content.
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
Being the owner of an 8" Schmidt–Cassegrain scope, this blows my mind.
It gripped her hand gently. 'Regret is for humans,' it said.
Right after submitting this I noticed my goof in the title. As a refracting telescope the primary optical device is a mirror, not a lens. Slapping myself in the face.
Most nostalgic old guy crapping on new stuff in a Slashdot post.
I swear to God...I swear to God! That is NOT how you treat your human!
he didnt bother to post any pictures captured with it. Only pictures of an ugly metal contraption.
Who logs in to gdm? Not I, said the duck.
Whether reflective, refractive, or with a bunch of electromagnets, a lens is designated not by what it is made of, or how it does what it does, but by the fact that it just does.
A lens by definition changes the physical size of a virtual image. This does not always mean that the virtual image gets smaller, or that the effect is in two, or even three dimensions. The physics world is full of FDDF/DFFD lenses, usually with some very good vacuum near the center.
Now about that coating... vacuum deposition is not out of the question as long as not to much area is "silvered" at a time. My own experience is with Gold, but the tech is easy enough: a reasonably stout container, a reasonably good vacuum pump, a sealant, (In the Biz, this was commonly called "Monkey Shit".), a thin wire of suitable material, some cabling, and a bunch of car batteries.
A slightly larger and more fun version of the old-fashioned Flash Bulb.
Frankly, Dobsonian mounts are a pain; I never saw the point of them myself. But with a couple of beefy servos, some drive electronics, an Arduino-level computer, and the mount could be made to track reasonably well for short period of times.
Years and years ago, around 1976, I had a tube type TV that went fritz so I took it to an Austin, Tx TV repair shop. The guy took it in the back to work on and while he was doing it I looked around his shop and there were quite a few very nice amateur astronomy photos, Jupiter, Saturn, the Moon and such. I was taking some astronomy classes at UT. When he came out we got talking and he told me he was into astronomy. Now, this shop was a WRECK, much like most TV repair shops I have ever seen. pretty much a dump. He asked me to come in the back to 'See something'. The guy was about 6'6" tall and BIG, and rough looking, and I am NOT, so I declined, but he insisted so I finally went through a maze of old junk, narrow dark halls, and finally got to the back of the store. I was kinda scared. He pointed to something on the ground. It was a round plug of glass on a large wooden palate. My jaw dropped, I asked him if it was what I thought and he confirmed it was a slug for a 6 ft telescope. I believe he said he got it at auction when a Swiss observatory had two made and the first worked out, so he got it cheap. It was unfinished, just a blob of glass, but at the time I'd only seen telescopes in the 36" range and this was huge! He was grinning ear to ear, and I was astounded. I believe his name was Chuck Knesek but I may be wrong or only close. It's been 35+ years. I never saw him again. If anyone knows what happened to him or his slug I'd love to know.
Actually, Ritchey-Chretien telescopes use a hyperbolic primary mirror....good enough for the Hubble Space Telescope
It's an impressive amateur engineering feat, but its performance as a telescope might not be anything to write home about. It probably shares one quality with the hubble that you wouldn't want: a problem with gravity.
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 wasn't until the later mission to fix it with some corrective optics that it really achieved its best capabilities.
Now, since the surplus 70" mirror this guy used was designed to work on a satellite, it would very likely have the same problem but in reverse. If the mirror was designed to be shaped properly in a microgravity environment, it would also be deformed when on earth (as it is when used in the amateur telescope.) That might make the images from it quite a bit worse than one might hope for from a 70" instrument.
Yep, more of these please.
I know nothing of Astrology* and telescopes, but these stories spark imagination.
*I know what word I typed.
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