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Hay Mark! DIY Telescopes!
Topic Started: Aug 18 2010, 11:55 AM (1,968 Views)
George K
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Finally
http://www.popularmechanics.com/science/space/telescopes/ambitious-incredible-diy-telescopes?click=pm_news

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The Shed Observatory
Face it, once you’ve successfully made your own telescope, you’ll probably be hooked.

The sixth telescope made by Shane LaPierre of Torrington, Connecticut, is so ambitious that, while he stores it in a shed-turned-observatory in his yard, it’s too big to be used inside. This telescope has a 20-inch mirror and is based on the Newtonian-Dobsonian design, with one big, curved mirror that collects and focuses light, while a second, diagonal mirror reflects it to a side-mounted eyepiece.

See that ladder on the ground? It’s needed to reach the eyepiece at the top of the scope. Stellafane’s observatory dome is directly behind.


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Bowling Ball Mount

There was no whimsy behind turning this bowling ball into a spherical mount that allows the telescope to be pointed in any direction. Douglas Arion says the smooth, polyurethane surface of a bowling ball makes a great spherical mount, especially when placed on a Teflon platform. He was even willing to pay retail at a big-box sporting goods store for this ball, but says they’re available used. A motorized version of this bowling-ball-mounted telescope won first prize for mechanics at Stellafane a few years back. There were no extra points awarded for the sparkles.

A guide to GKSR: Click

"Now look here, you Baltic gas passer... "
- Mik, 6/14/08


Nothing is as effective as homeopathy.

I'd rather listen to an hour of Abba than an hour of The Beatles.
- Klaus, 4/29/18
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Klaus
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HOLY CARP!!!
I had an 8" Dobson once. From what I heard they are relatively easy to build, and even 32" Dobson's are not uncommon anymore.

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Trifonov Fleisher Klaus Sokolov Zimmerman
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Mark
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HOLY CARP!!!
Talk about destroying someone's dark adaptation!

Oh man I would be so pissed!
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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
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Luke's Dad
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Emperor Pengin
??
The problem with having an open mind is that people keep trying to put things in it.
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JBryan
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I am the grey one
I think he is talking about the flash photo.
"Any man who would make an X rated movie should be forced to take his daughter to see it". - John Wayne


There is a line we cross when we go from "I will believe it when I see it" to "I will see it when I believe it".


Henry II: I marvel at you after all these years. Still like a democratic drawbridge: going down for everybody.

Eleanor: At my age there's not much traffic anymore.

From The Lion in Winter.
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George K
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Finally
Klaus
Aug 18 2010, 12:16 PM
I had an 8" Dobson once. From what I heard they are relatively easy to build, and even 32" Dobson's are not uncommon anymore.
http://www.popularmechanics.com/science/space/telescopes/4286700

Build your own:
Quote:
 
When I set out to build a portable telescope, known as a Dobsonian telescope, the first step had me stymied—where do you find 6 ft of 8-in.-dia cardboard tubing?

I'm a physicist by training, an amateur astronomer by inclination and an occasional visitor to the home center for DIY projects. A massive tube is not usually on my shopping list. I stood in the store with meticulous notes on the materials I needed, but no one could find them. "Um, I think it might be called Sonotube," I repeated, until someone pointed me toward the concrete form tubes in the garden area. And no, my local hardware store did not carry Teflon.

I had heard that building a Dobsonian was simple and inexpensive. This is in fact true—but collecting the materials takes some doing. This is a far cry from John Dobson's experience when he first built the portable, sidewalk telescopes that now bear his name. "We were just scroungers," he tells PM. "The whole thing was made out of junk. The cardboard tubes were lying around. The shingles used to mount the mirror were blown off roofs in storms. We built the mount from window cutouts from schoolhouse doors that had been thrown away." At age 91, Dobson is as passionate about building inexpensive telescopes as he was when he built his first one in 1956. When I brag that the plastics supply store where I finally found Teflon gave me some scrap for free, he exclaims, "Good for you!"

I did not admit to him that I didn't grind my own telescope mirrors—something he did with two porthole windows and sand paper—and that I didn't build my own eyepiece out of binoculars. (Optics these days can be purchased in kits online.) Nonetheless, the instructions I used were very similar to Dobson's original Plans for Building A Sidewalk Telescope. I based my design on the telescope plans provided by Ray Cash, a member of the San Francisco Sidewalk Astronomers, modifying the plans even further with a few ready-made parts.

Dobson claims he didn't invent the sidewalk telescope, as he had lots of help with his early prototypes. However, Dobson did choose to promote his sidewalk telescopes at the cost of his longtime home. After 23 years living in a Vedanta (a branch of Hinduism) monastery, where he built telescopes surreptitiously in the basement and then snuck out at night to introduce the neighborhood kids to the stars, he was told he had to choose between life as a monk or as a telescope builder. That was in 1967. Today, Dobson still tours the world to teach telescope building. The collection process turned out to be an enjoyable treasure hunt—but don't worry, the source list we put together below explains how to find everything. As I sawed and drilled, I murmured a fairly steady mantra to myself of "Why on earth do I have to do that? Oh. Wow. That's brilliant." The design isn't intuitive or obvious, but it is wonderfully elegant.

In essence, it's a telescope built onto a gun mount, which balances through friction as it swivels on an LP record. My total cost was around $400. You may be able to buy a similarly sized commercial telescope at that price these days, but you wouldn't have nearly as much fun. The actual construction took a weekend, and it would be a great project to tackle with kids.

Dobson may be nonchalant about how he used only junk to build his scopes, but it took an impressive mind to figure out how to use that junk in such ingenious ways. Building my telescope, watching it swivel so smoothly, seeing the stars, I basked in the reflected glory of that ingenuity. I am hooked. I want to build another one—and next time, I'm going to grind my own mirrors.

A guide to GKSR: Click

"Now look here, you Baltic gas passer... "
- Mik, 6/14/08


Nothing is as effective as homeopathy.

I'd rather listen to an hour of Abba than an hour of The Beatles.
- Klaus, 4/29/18
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Luke's Dad
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Emperor Pengin
Ahh. Hey Mark, my dad just picked up one of these:

http://www0.epinions.com/review/Celestron_NexStar_6SE_Telescope/content_343204793988

Nothing too fancy but it gets some pretty good reviews. Any ideas for a camera to go with it. I'm thinking about getting one for him for his birthday. It's supposed to be compatible with a good many cameras.
The problem with having an open mind is that people keep trying to put things in it.
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OperaTenor
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Pisa-Carp
Klaus
Aug 18 2010, 12:16 PM
I had an 8" Dobson once.
Oh my. Did you lose it in some sort of industrial accident?

BTW, we refer to them as "Johnsons" here in the US.



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Mark
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HOLY CARP!!!
Luke's Dad
Aug 18 2010, 03:47 PM
Ahh. Hey Mark, my dad just picked up one of these:

http://www0.epinions.com/review/Celestron_NexStar_6SE_Telescope/content_343204793988

Nothing too fancy but it gets some pretty good reviews. Any ideas for a camera to go with it. I'm thinking about getting one for him for his birthday. It's supposed to be compatible with a good many cameras.
Um, from the review site you linked...

Posted Image

I highlighted what I also already know about this telescope.

It is fine for visual astronomy.
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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
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George K
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Finally
OperaTenor
Aug 18 2010, 04:13 PM
Klaus
Aug 18 2010, 12:16 PM
I had an 8" Dobson once.
Oh my. Did you lose it in some sort of industrial accident?

BTW, we refer to them as "Johnsons" here in the US.

:rimshot:
A guide to GKSR: Click

"Now look here, you Baltic gas passer... "
- Mik, 6/14/08


Nothing is as effective as homeopathy.

I'd rather listen to an hour of Abba than an hour of The Beatles.
- Klaus, 4/29/18
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Mikhailoh
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If you want trouble, find yourself a redhead
OperaTenor
Aug 18 2010, 04:13 PM
Klaus
Aug 18 2010, 12:16 PM
I had an 8" Dobson once.
Oh my. Did you lose it in some sort of industrial accident?

BTW, we refer to them as "Johnsons" here in the US.

I think he's making that 32" up.
Once in his life, every man is entitled to fall madly in love with a gorgeous redhead - Lucille Ball
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OperaTenor
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Pisa-Carp
One man's 32" is one woman's 8", doncha know...


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Klaus
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HOLY CARP!!!
Ah, that Dobson I still have. But I will not talk about it. I don't want to embarass you :D

Actually I sold the "other" Dobson a few months after I bought it. I was somewhat frustrated by the fact that I can't see anything with it that I cannot see in 100x better quality on the internet. Also, picking up this hobby more seriously would have required enormous amounts of (night) time and money (e.g. from what I understand one needs to spend at least $10K for equipment if you want to make decent astro photos). Hence I decided to give up. But it was still an interesting experience.
Trifonov Fleisher Klaus Sokolov Zimmerman
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