DIY octagonal wooden 8" dob project

[Moonshane]

this will be a beautiful scope.

apart from the obvious general quality and style of the thing, I like the simple solutions to potential problems like raising the focuser with a shaped wooden block to be in optimum focal position - I'll be using that one I think.

[Astrokev]

this will be a beautiful scope.

apart from the obvious general quality and style of the thing, I like the simple solutions to potential problems like raising the focuser with a shaped wooden block to be in optimum focal position - I'll be using that one I think.

Likewise!

[Astrokev]

Crackin' woodworking chaps. How well does wood stand up to being stored in an obsy?

No idea, I don't have an observatory (not yet anyway). When I used my old wooden tube it was stored in the house (and latterly a shed). Never noticed any problems.

[Penguin Pete]

Crackin' woodworking chaps. How well does wood stand up to being stored in an obsy?

Well, it shouldn't have too much problem with rust :-)

I have limited experience in this sort of thing but wood doesn't like sudden changes or extremes of humidity. One problem is that it can become permanently compressed if it becomes very wet whilst being held rigidly and is unable to swell. Then, when it dries out it cracks. This is unlikely to be an issue in a decent shed or observatory though I would have thought. Would heat in the summer be an issue? I don't know how hot they get.

In general I imagine that if it's suitable for a mirror it's probably ok for the wood too. Walnut is dimensionally pretty stable and ply should have little problem.

[Penguin Pete]

I'd love a little advice from anyone who has used a dob. Is weight an issue for the base? I don't need to move it far for use and am thinking that leaving it on the heavy side might help keep it solid in use.

Secondly, I have searched these forums and it seems that a good angle between the teflon glides for the altitude bearing is 70°, perhaps better than 90°. An thoughts?

Many thanks,

Pete

[Moonshane]

hi Peter

first teflon pads for the alt bearings - definitely between 65-75 degrees. 70 is optimum. per Kreige and Berry who know a thing or two.

also yes, I agree that a stable heavy base is ideal. the lower the better really. but with a small mirror there's not too much weight in the tube at the mirror end so you end up with a higher base as the balance point is higher up. I think that a base perhaps 1.5x the OTA diameter is ideal for the footprint in these circumstances. with heavier mirrors then you can minimise the footprint as the COG is much lower down.

I made this for a friend and a 6" f5. not as aesthetically pleasing as yours but worked very well indeed.

http://stargazerslounge.com/diy-astronomer/144997-home-made-dobsonian-base.html

[Penguin Pete]

Many thanks Moonshane - sounds good.

[Penguin Pete]

Finally fished the base. Many thanks for your helpful ideas everyone.

[Gina]

My word! That's beautiful

[Anders]

Wow, that is just amazingly good looking!

Awesome work,

//Anders

[Moonshane]

brilliant result and scope.

[gary1968]

That is one stunning looking scope, you are quite the craftsman...... It will be worth the effort once the base is built...

Gary

[m.tweedy]

Lovely. Can you not face the telrad in wood to keep the look

[Penguin Pete]

Thanks for the nice comments. Here's a shot of the underside of the base, as the feet rather disappeared in the long grass of the previous photo.

[Astrokev]

Beautiful. Excellent job!

[fwm891]

I love to see good woodwork - and that's really good woodwork

[Gina]

Oh so do I - it's a joy to behold

[Penguin Pete]

Lovely. Can you not face the telrad in wood to keep the look

Hmm, thanks, interesting idea as that large expanse of black plastic always bothered me and that would be quite quick and easy. Rebuilding it in wood would be another idea but I'm not sure I've got time for that.

[michael.h.f.wilkinson]

Really nice. It very much reminds me of my old 6" Newtonian, in particular after I rebuilt it. The tube had almost exactly the same design. The mount I made was not nearly as good as yours.

[deebster]

What a beautiful piece of work

I need a takes-hat-off emoticon

[George]

I wouldn't be ashamed to have that as a talking point in my living room, lovely craftsmanship and I do like wood to look natural

[m.tweedy]

Hmm, thanks, interesting idea as that large expanse of black plastic always bothered me and that would be quite quick and easy. Rebuilding it in wood would be another idea but I'm not sure I've got time for that.

Go on I am sure you can "make" some time:). to me it would be the icing on the cake

[spaceboy]

Stunning piece of craftsmanship. A true talent to produce such an elegant finish you must be very proud of the out come.