Wooden octagonal tube telescope

[Rod]

I have just finished refurbishing an old 6 inch newt I built over 20 years ago. It has an f5 mirror I made and was originally mounted in a traditional cardboard tube and dob mount.

I wanted to make this version look a bit more attractive and decided to make an octagonal tube and copy some ideas I had seen on the net.

To improve the look, the ply edges on the mount are finished with jarrah. The circular ply base has a piece of Tasmanian oak wrapped around it.

I got the jarrah edging idea from Ian's thread:

http://www.iceinspace.com.au/forum/s...t=Plywood+tube

The technique for making the octagon a came from here:

http://www.gregorystrike.com/2010/05...r-telescope-2/

Some idea for the mount design came from here:

https://instructablesrss.wordpress.c...ube-and-mount/

I had some helpful advice on two other threads on how to finish the tube and balance it. I learnt that small tubes like this with heavy focusers and eyepieces need to be balanced across their widths as well as their length. In this case I had to move the altitude bearings 13 mm up from centre. Alex (mentalforastro) contacted me privately and went over this in some detail. The tube is now well balanced at all elevations with medium and light eyepieces. Heavy eyepieces might need a small counterweight but only at low altitude.

Thanks Alex!

Rod

[Rod]

Another pic

[glend (Glen)]

Very, nice work Rod, I am a big advocate of natural materials in my scope builds. As a practicality against water (Dew) getting into the ply end grain and causing delamination can I make one suggestion:
if you get some small Jarrah edging/molding and cap the end grain it would finish it off nicely and prevent moisture getting in the ends. An alternative might be to just paint the end grain with something like boat builders epoxy (which will stop water penetration), and then over coat that with a dark coloured paint to match the timber.

[Rod]

Here is how the tube was made. The wood was 6mm thick Russian Birch. They have 22.5 degrees edge cut on each edge. I used a router bit which cuts that angle. The router was mounted in a router table. Cutting all the edges only took a few minutes.

Every second piece has a jarrah laminate.

You tape the pieces together with the narrow edge faced down. Then the whole thing is turned over and polyurethane glue used to fill the v shaped groove between the planks. I made up some circular clamps from hose clamps to hold it together while it dried.

These pics are of another octagonal tube I made with my son. I used the same process on this scope. Sorry for the extra posts for some reason I am only able to post one pic at a time with my iPad.

[Rod]

All clamped up

[Rod]

Looking down the inside

[FlashDrive (Poppy)]

Love your work Rod .... great outcome.

Col...

[Big Dave (Dave)]

Very nice work.

[anj026]

Good job Rod.

I am a big fan of ply octagonal tubes myself.

[Rod]

Thanks for the nice comments.

Glen I agree some jarrah on the tube ends would be a good idea. I have some thin offcut strips. I am going to thinks about the best way to attach them and file them to fit. I am a bit nervous about using a router on the finished tube so might just use hand tools.

Rod

[anj026]

Hi Rod

You might like this website from Japan. On the "My telescopes" page is a good description of a ply reflector tube.

http://www.geocities.jp/toshimi_taki/