Building an oak telescope

You might not think about the finish of your homemade telescope but if it’s build from solid oak you probably should. [Gregory Strike] built this 8″ telescope a few years back but just posted about it a few days ago. The optics are quite expensive but the rest of the build was done dirt cheap and he did a great job of it.That includes taking care to finish the oak boards that make up the octagonal body of the instrument.

This is much more approachable for the average hacker than something like the 22″ binocular build (or going way too far and building your own observatory). [Gregory] developed his design after looking at a couple of others. If you need a bit of a push to get started check out the telescope resource we ran across in our days of Internet infancy.

26 thoughts on “Building an oak telescope

  1. As an amateur astronomer, I have to say this is a bad idea. 8″ telescopes are hard enough to lug around without having them made of something as heavy as wood.

    Still, it does look beautiful.

  2. Doesn’t wood change dimensions quickly based on temperature and humidity? I would think it would never stay in focus or in position. To me, the material seems unstable … and a bad idea.

  3. Are we talking about an 8 inch Telescope or an 8 foot Telescope??? inches=” and Feet=’… Looks like 8 foot in the Pic. Big difference…

    Don

    1. Hope I’m not feeding a troll. The size refers to the diameter of the objective lens in a refractive telescope or the diameter of the primary mirror in a Newtonian telescope. I apologize if that was a intended as a serious comment

  4. If you do this make sure you mount your optics on an interior metal frame instead of directly to the wood. Wood changes shape quite drastically(as far as detailed optics are concerned) in different temperature and humidity.

  5. @mlseim Doh, you beat me to it. Yes it changes quite a lot. I have tried to make telescopes from wood and taking them outside in peak seasons makes them all but unusable.

  6. @Don

    I think the 8″ is the diameter of the lens… I could be wrong tho, I thought the same thing at first.

  7. For clarification, there isn’t a lens in the scope it’s a mirror.

    The mirror itself has a 8 inch diameter. The bigger the mirror the more light you can gather (it’s like having an 8 inch pupil). The OTA (tube) itself is 4ft long. And yes, the scope is definitely a pain to lug around! :) But at least it looks good sitting in my dining room!

  8. Yes, 8 inches would definitely be the width of the mirror.

    The width of your optics is the important parameter since it determines how much light you can collect, the other dimensions are pretty much irrelevant AFAIK.

  9. @j9: That type of axis/azimuth mount is actually quite common for large home-built telescopes meant for observing deep sky objects. It lets you cheaply mount a pretty large telescope, and it breaks down easily for transport. Obviously you can’t use it for photography like you would an equatoral mount, but otherwise it’s a pretty effective choice.

  10. Re: the use of wood as a material for telescope tubes.

    It’s fine, if a bit too heavy. Dimensional stability isn’t really that big of a deal for most amateur scopes which are used visually. Slight expansion along the length of the telescope tube results in a small shift in focus, but no other significant errors. Shifts in the tube radius will generally keep a centered diagonal centered, and cause no real additional problem.

    It’s common to use cardboard tubes used in the concrete industry (“Sonotube”, and related products) as telescope tools. Despite the apparent cheapness, it’s actually a fine material for scopes of this size. It’s cheap, easy to paint, strong enough, and easily available. Yes, you have to waterproof them (I like to use a durable poly floor paint) and I wouldn’t leave them out in the rain or in a high humidity environment, but would you do that to a camera?

    One of the past members of our workshop, Phil Alotis, did a similar scope in years past. It appeared in Sky & Telescope, and was called Christine. You can see it on the left here:

    If my memory serves, his wife was the motivating factor, she said that if he was going to store the scope inside, it had to look pretty. The resulting scope is beautiful, but massive. I think the mass means that it cools relatively slowly, which can be a disadvantage as well. I believe it was also an award winner at the Riverside Telescope Maker’s Conference.

  11. @Gregory… Ok, now I get it:) I know very little about Telescopes. Obviously… So, thanks for the explanation. Guess, to you guys. It’s like us computer geeks saying… I run Fedora Linux on my Box. I think you should just mount that tele in the back of my 76 Blazer 4×4 and then help me get the 200+lbs Removable Top off, so we can drive out to the Country to see the stars:)

    Don

  12. Dobsonian type telescopes are made of everything and anything. They’re real time viewing instruments (no photography, no auto-tracking) so it’s all about the size and quality of the optics. 8″ isn’t very big these days for dob’s – especially if you have to lug around a heavy mount and tube.

    http://www.google.com/images?q=dobsonian+telescope

    Now here’s a big amateur scope

  13. temperature has little effect. it is the humidity that screws with wood. wood expands along the grain not across it. If you treat your wood with a proper finish you lock out all the moisture and can make it very very stable.

  14. @tehodore

    Pluto was discovered by Clyde Tombaugh at the LOWELL OBSERVATORY. Hardly a “home brewed” scope.

  15. Clyde Tombaugh didn’t discover Pluto with a handmade telescope, but he did land a job at the Lowell observatory as a young man after submitting sketches of Jupiter and Mars that he _did_ make using a home made telescope of 9″ aperture. He constructed a larger 16″ telescope that was bought by an amateur after Clyde’s death, and reassembled. Check it out:

    http://cs.astronomy.com/asycs/blogs/astronomy/2009/01/28/on-the-road-working-on-a-classic.aspx

  16. TEKSAVVY now offers Cable internet and ADSL internet (Canada) – customer for 3 months, you are automatically entered into the contest. If you’re not lucky enough to win the grand prize, you can still win as 2nd place gets 1 year of free service and 3rd place gets 6 months of free service… Customer! have a chance Win $1000.00 — torontointernet.blogspot.com

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