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Thread: DIY Telescope

  1. #1
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    DIY Telescope

    Is it possible to make a reasonably decent telescope for little money? I'm thinking 500US.
    I know that I know nothing, so I question everything. - Socrates/Descartes

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    Quote Originally Posted by DaCaptain View Post
    Is it possible to make a reasonably decent telescope for little money? I'm thinking 500US.
    The major part of the cost in most telescopes is the optics, so unless you are able to grind these yourself to a satisfactory standard, you will have a cost issue to get them. It depends on what you want to use it for, but you could get a very nice Dobsonian-mounted Newtonian telescope for $US500.

    If you are just looking for a DIY woodwork project however, buying a cheapish Newtonian telescope and building a Dob mount for it can be quite fun.

  3. #3
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    It is possible, but it is a lot of work.

    Contact your local astronomy club. They will have plenty to share about building your own scope.

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    Yeah. And what AGN Fuel said.

  5. #5
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    Basically what AGN Fuel wrote, but basically a telescope is just a lens and an eyepiece mounted into a tube. Most of the cost is going to be the lens and the eyepiece, so if you want to make them yourself you'll save money but it's a very tough task. And if you get the optics and mount them yourself, you are only saving the cost of a tube and some bolts, so you're not going to save that much. I guess you could also make an equatorial mount yourself, but that would seem pretty involved as well.
    As above, so below

  6. #6
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    Quote Originally Posted by DaCaptain View Post
    Is it possible to make a reasonably decent telescope for little money? I'm thinking 500US.
    I think it would be difficult to make ONE telescope at a lower price per instrument that what the cheap dobsonians cost. If you're talking about $500, the cost of the grinding tools and abrasives and the jigs and testing apparatus will quickly add up to more than you'd save. That being said there is some self-education, and personal validation from doing it that might make the effort worth while.
    Post edit... I see this is also the same advice AGN Fuel gave.
    Forming opinions as we speak

  7. #7
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    at school last century we made a telescope, ground and polished the mirror, made a wooden frame and bought second hand prism and lenses plus a spotting scope, it took one whole term under supervision of (unlikely I know) our biology teacher. No idea of the budget but not too bad, silvering the mirror probably the most cost. It worked too. Not exactly portable though, it was about eight feet long.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  8. #8
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    As others have said it is hard nowadays to compete with the mass-produced telescopes if you just want to save money at least if you want a small to medium scope of conventional construction. Most people who build telescopes today do it for the challenge or to build something unusual. Two of my favorite telescopes are home built, a 2x38 cm bino-Dobson and an air transportable 38 cm Dobson that can be split into a case and a carry on luggage. Nowhere near 500$ though and it requires quite a bit of previous experience with telescopes.

  9. #9
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    My first DIY was a 6" f/8 reflector in 1964-65, when an Edmund Scientific mirror making kit could be had for about $12 and a Kraft board tube for about $7. Total cost was under $50, compared with about $200 for an Edmund or Criterion scope. A couple of caveats: I had the benefit of my dad's table saw and other shop tools, along with what he had taught me about using them, for building a mount, and he knew someone at work who could get the mirror aluminized free of charge.

    In 1985 I built a 17.5" Dob with a Coulter mirror and diagonal for about $550 and less than $200 for lumber. Coulter's production scope was close to $1,200 and twice the weight of mine, which is a truss tube assembly and a correspondingly lighter rocker and ground board assembly. The same table saw served well for this one.

  10. #10
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    Thanks all for the replies. I was thinking that I'd be able to get more scope for my money if I built it myself. Didn't know most the cost was in the mirror and eyepiece. I didn't even know what scope would be a good one to start with. A Dobsonian is in my near future.

    Are there any other extras I might want to get to improve my night time viewing?
    Last edited by DaCaptain; 2017-May-11 at 02:32 PM.
    I know that I know nothing, so I question everything. - Socrates/Descartes

  11. #11
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    Quote Originally Posted by DaCaptain View Post
    ... Are there any other extras I might want to get to improve my night time viewing?
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    Forming opinions as we speak

  12. #12
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    Quote Originally Posted by DaCaptain View Post

    Are there any other extras I might want to get to improve my night time viewing?
    One of the major obstacles is physical discomfort while viewing. Warm, comfortable clothing is essential. Being able to sit while using a small telescope might be more productive (fun) than having to stand crouched over something larger.
    Selden

  13. #13
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    A couple of decades ago, I had it in mind to build a 10" Dobsonian after seeing an article on making a tube from wood slats using canoe-making techniques. Well, I built the tube but not the telescope. And I still have the tube. Someday, maybe, I'll get back to it.

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    If I build the scope myself, what material would be best for the tube? Can I just go to Home Depot and buy a 10" concrete tube, $11?
    I know that I know nothing, so I question everything. - Socrates/Descartes

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    Quote Originally Posted by DaCaptain View Post
    If I build the scope myself, what material would be best for the tube? Can I just go to Home Depot and buy a 10" concrete tube, $11?
    I remember Coulter Optics (years ago) suggesting exactly that. Get one with with a diameter wide enough to give you some room... that is build or buy the mirror position adjustment mechanism, and then buy the tube to fit it.
    Forming opinions as we speak

  16. #16
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    Quote Originally Posted by DaCaptain View Post
    If I build the scope myself, what material would be best for the tube? Can I just go to Home Depot and buy a 10" concrete tube, $11?
    That is just what John Dobson himself used for his big scopes. He had plenty of strong backs in his club to help him move it. I chose to build a wooden truss to make it lighter.

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    Quote Originally Posted by Hornblower View Post
    That is just what John Dobson himself used for his big scopes. He had plenty of strong backs in his club to help him move it. I chose to build a wooden truss to make it lighter.
    I've never tried this, but I imagine the greater weight may also play havoc with the tube's CoG and the pivot points in elevation. The pivot points have to have sufficient friction to prevent the tube swinging by itself due to the CoG moving further from the axis (e.g. when viewing objects at a low altitude), but not so much that it becomes difficult to move at all.

    I certainly stand to be corrected, but I would have thought a concrete tube would make this a greater problem (greater friction required to counteract the greater force = more difficult to move to track an object manually as it crosses and then leaves the FoV). A wooden tube would seem to be a more versatile choice. On the plus side though - you would have had a good workout by the end of the night's viewing!

  18. #18
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    DIY Telescope

    Quote Originally Posted by AGN Fuel View Post
    I've never tried this, but I imagine the greater weight may also play havoc with the tube's CoG and the pivot points in elevation. The pivot points have to have sufficient friction to prevent the tube swinging by itself due to the CoG moving further from the axis (e.g. when viewing objects at a low altitude), but not so much that it becomes difficult to move at all.

    I certainly stand to be corrected, but I would have thought a concrete tube would make this a greater problem (greater friction required to counteract the greater force = more difficult to move to track an object manually as it crosses and then leaves the FoV). A wooden tube would seem to be a more versatile choice. On the plus side though - you would have had a good workout by the end of the night's viewing!
    While concrete tube forms are available from other manufacturers, Sonotube has become a generic name throughout the industry, much like Kleenex. Being basically a cardboard product, I think they are only slightly denser than commonly used wood.
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  19. #19
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    I would choose sonotube over concrete but make it more waterproof with a PVA wash or better still a polyester resin wash. If you make the resin thinner (styrene usually) it will also penetrate and add strength and stiffness too. And a little extra weight.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  20. #20
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    My hunch is that when DaCaptain said "concrete tube", he meant Sonotube or something similar, which is used as a form for pouring cylindrical concrete columns.

  21. #21
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    Quote Originally Posted by AGN Fuel View Post
    I've never tried this, but I imagine the greater weight may also play havoc with the tube's CoG and the pivot points in elevation. The pivot points have to have sufficient friction to prevent the tube swinging by itself due to the CoG moving further from the axis (e.g. when viewing objects at a low altitude), but not so much that it becomes difficult to move at all.

    I certainly stand to be corrected, but I would have thought a concrete tube would make this a greater problem (greater friction required to counteract the greater force = more difficult to move to track an object manually as it crosses and then leaves the FoV). A wooden tube would seem to be a more versatile choice. On the plus side though - you would have had a good workout by the end of the night's viewing!
    I don't think anyone depends on altitude bearing friction to keep a badly unbalanced tube assembly from nosing over. We either place the center of mass at the pivot point or use springs as a counterpoise.

    My homemade wooden truss 17.5" Dob with Coulter optics started out about 140 pounds all up, while Coulter's production model with its solid Sonotube tube assembly and correspondingly heavier rocker box was about 270 pounds. My altitude pivot point is about 1/5 of the way from the primary mirror to the front end. I think Coulter's pivot point was higher. By the time I put a 9x50 finder and a rather heavy homemade reflex finder on the secondary cage I realized I had not allowed for their weight, and I added 9 pounds of counterweights to the backside of the mirror cell. The total weight now is about 150 pounds.

  22. #22
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    Quote Originally Posted by Hornblower View Post
    I don't think anyone depends on altitude bearing friction to keep a badly unbalanced tube assembly from nosing over. We either place the center of mass at the pivot point or use springs as a counterpoise.

    My homemade wooden truss 17.5" Dob with Coulter optics started out about 140 pounds all up, while Coulter's production model with its solid Sonotube tube assembly and correspondingly heavier rocker box was about 270 pounds. My altitude pivot point is about 1/5 of the way from the primary mirror to the front end. I think Coulter's pivot point was higher. By the time I put a 9x50 finder and a rather heavy homemade reflex finder on the secondary cage I realized I had not allowed for their weight, and I added 9 pounds of counterweights to the backside of the mirror cell. The total weight now is about 150 pounds.
    Yes, I had a complete D'oh moment about 30 seconds after I made that post - the problems I was envisaging could be easily resolved with counterweights.

    I am not familiar with Sonotube. I wonder if it has a different tradename in Australia? I will check this out - it sounds like an extremely interesting product for a number of uses.

    (Just checked - it's retailed as 'Formatube' here. I didn't realise DaCaptain meant a concrete form tube. This all makes a lot more sense now!! )
    Last edited by AGN Fuel; 2017-May-19 at 02:01 AM.

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    Moved from Q&A as I think it is specific enough to be better placed in this forum.
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  24. #24
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    Quote Originally Posted by AGN Fuel View Post
    Yes, I had a complete D'oh moment about 30 seconds after I made that post - the problems I was envisaging could be easily resolved with counterweights.

    I am not familiar with Sonotube. I wonder if it has a different tradename in Australia? I will check this out - it sounds like an extremely interesting product for a number of uses.

    (Just checked - it's retailed as 'Formatube' here. I didn't realise DaCaptain meant a concrete form tube. This all makes a lot more sense now!! )
    LOL, I was wondering why people thought the scope was going to be hard to balance or move. My mistake.
    I know that I know nothing, so I question everything. - Socrates/Descartes

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