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Carbon Fibre Telescope Finished

paul11

By paul11
in DIY Astronomer

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skybadger

skybadger

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Paul

This is all really useful stuff. Like I was wondering how you got the hard edges on teh tube ends - I thuoght you might have had tube stops. Now I know. What if you had cast tube end rings and used them on the card tube ?

I am planning ot use the router to cut GRP casting moulds for the spider and mirror cell. I'll tell you how that turns out.

I guess the cutting of the tube end depends on the tube being cute straight. If not - is there a plan b? I have seen methods using rollers to roll the tube on against a blade

The other method I saw forlaying up a tube involved wooden formers on a pole around which a form of GRP resistant Acetate was wrapped for a smooth surface to later remove from. Might be easier to use than cardboard. there they used bodyfiller before sanding to give the good surface finish with gloss layers added on top.

Finally, any considerations for internal stiffening rings or baffles cast from GRP/CFRP, what are the outer fixing rings made from ? and are you using a lazy susan bearing to cut circles with the bandsaw ?

thanks for your very informative sequence

Mike

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paul11

paul11

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Paul

This is all really useful stuff. Like I was wondering how you got the hard edges on teh tube ends - I thuoght you might have had tube stops. Now I know. What if you had cast tube end rings and used them on the card tube ?

I am planning ot use the router to cut GRP casting moulds for the spider and mirror cell. I'll tell you how that turns out.

I guess the cutting of the tube end depends on the tube being cute straight. If not - is there a plan b? I have seen methods using rollers to roll the tube on against a blade

The other method I saw forlaying up a tube involved wooden formers on a pole around which a form of GRP resistant Acetate was wrapped for a smooth surface to later remove from. Might be easier to use than cardboard. there they used bodyfiller before sanding to give the good surface finish with gloss layers added on top.

Finally, any considerations for internal stiffening rings or baffles cast from GRP/CFRP, what are the outer fixing rings made from ? and are you using a lazy susan bearing to cut circles with the bandsaw ?

thanks for your very informative sequence

Mike

Hi Mike, I would not change anything on the tube ends, the tube is the same all over and it is very strong. As for a plan B on cutting the end of the tube, you don’t need one. Whatever former you use for a tube must be cut square so it makes it easy to cut it to length. You can’t go wrong with the Router because with the fence set it won’t allow you to cut into the tube accidently. As for the use of wooden formers it really is whatever works. I’ve been asked to make a tube for someone and I am going to use a cardboard tube again but I will fill and sand it up this time. I’m not sure if I am going to fit baffles yet but I can tell you the tube defiantly will not need any internal stiffening rings it is so strong I’m sure I could lay it on the floor and stand on it and I weigh 13 stone. When you talk about the outer fixing rings are you talking about the tube rings? And yes I am using a kind of lazy susan and I will post some images of that later,,,,Paul.

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paul11

paul11

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That is just great paul, If someone said to you could you make me a 10" F7 or F 8 tube would you do it, and how much would you charge ? how heavy do you think it would be, compared to aluminium ? what do you think its thermal properties would compare like ?

The cost to make a tube like that would be approx £450.

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paul11

paul11

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Hi all I managed to get an hour in tonight to give this scope a test run. I changed the springs in the cell to 25lb and made a slight alteration to the way the mirror was held in and it’s holding collimation a lot better. The image is single shot from a DSLR at prime and 1/400 sec. I think I’m happy with the image but I have got a bit more testing to do. What do you think of the image guys?,,,,Paul.

post-15572-133877411716_thumb.jpg

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Starflyer

Starflyer

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That's a great result and a beautiful 'scope.

What software did you do use to plan the layout of the scope, or was it just your intuition? Have you taken any flats to analyse the field illumination / vignetting?

Where abouts are you based, I'd be interested in a tube for my 10" f/6.3 mirror set but I'm sure a fair few people have already contacted you and there must be a queue forming already :headbang:

Cheers,

Ian

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neil phillips

neil phillips

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Ok cheers Paul thanks for the quote. I love imaging, but my skills in doing things like you, are seriously lacking. ( wish they wasnt ) you are very skilled.

I kind of wondered if there was benefits over a ally tube, hence the other questions.

I wondered what a scope with one of your tubes, a great set of optics, a curved single vane spider, fully flocked tube. Antares 1/30th flat Orion 9 point cell, and fans would perform like against what i achieved, with my 1/10th wave set of orion optics Europa ( but with fan) wooden 3 point cell.

The scope wasnt top spec. but performed well. just wondered if you would have taken a interest in a scope being built like that, with your skills at its heart.

( The tube) But im seriously not rich, as such i would have to have sold my 12" Custom f6 1/12th pv SPX 300 to fund a project like that. Not something to take lightly sure you agree.

Neil phillips lunar and planetary images

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paul11

paul11

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That's a great result and a beautiful 'scope.

What software did you do use to plan the layout of the scope, or was it just your intuition? Have you taken any flats to analyse the field illumination / vignetting?

Where abouts are you based, I'd be interested in a tube for my 10" f/6.3 mirror set but I'm sure a fair few people have already contacted you and there must be a queue forming already :headbang:

Cheers,

Ian

Hi Ian I used NEWTWIN to design the scope with a few ideas of my own as well. I haven’t taken any flats to analyse the field illumination / vignetting yet. I live in Essex on Canvey Island, and I will send you a PM,,,,Paul.

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paul11

paul11

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Ok cheers Paul thanks for the quote. I love imaging, but my skills in doing things like you, are seriously lacking. ( wish they wasnt ) you are very skilled.

I kind of wondered if there was benefits over a ally tube, hence the other questions.

I wondered what a scope with one of your tubes, a great set of optics, a curved single vane spider, fully flocked tube. Antares 1/30th flat Orion 9 point cell, and fans would perform like against what i achieved, with my 1/10th wave set of orion optics Europa ( but with fan) wooden 3 point cell.

The scope wasnt top spec. but performed well. just wondered if you would have taken a interest in a scope being built like that, with your skills at its heart.

( The tube) But im seriously not rich, as such i would have to have sold my 12" Custom f6 1/12th pv SPX 300 to fund a project like that. Not something to take lightly sure you agree.

Neil phillips lunar and planetary images

Hi Neil I can see you love imaging I looked at all the images on your site and they are excellent, you are years ahead of me on that one. As far as I know C/F is the most stable material to use for a tube thermally and for strength. The scope you describe should work very well, if you use all the best materials available you can’t go far wrong. That is what I am going to build next with a 14” F5 mirror that I will start grinding after Christmas, I will send you a PM,,,,Paul.

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  • 1 month later...
Tim

Tim

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I have only just noticed this thread. What a superb project! I'd love to build an orion optics AG12 for 20% of the price!

Is the CF tube easy to work, seal, cut etc, for instance the cut out for the secondary?

Whilst checking sites earlier, I found a direct comparison graph with CF vs GRP and Aluminium tubes. The CF was not only stronger than the alu, it was a lot lighter and also more thermally stable.

Great thread, great project.

Tim

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  • 1 month later...
paul11

paul11

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Hi Tim, I found the C/F very easy to work with, it’s easy to cut and drill. I cut out the focuser hole with a core cutter it took about 5 seconds. The one thing I really like about the C/F is the inside of the tube and the mirrors are always dry and clear even after 10 hours, the outside is very wet but that’s ok. The reason for this could be the corematt between the layers of C/F, hope that helps,,,Paul.

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  • 3 weeks later...
LuKo78

LuKo78

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Hello,

I would like to ask for the materials used. I found Coremat 3mm, but I never found use carbon cloth. This is a unidirectional carbon fabric grid connected? What is the weight used? 150g/m2

Thank you for the information.

Lukas

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