Truss Dob project

[PatG]

Contemplating building a truss dob for some time.

Not sure what size at this point, likely between 12-18” perhaps.

Reasonably confident on the joinery aspects but are there any:

1) sources / suppliers of plans? 

2) suppliers of specialist parts including truss poles, truss brackets / connectors etc and mirror cells here in the UK?

Any other recommendations / tips from Dob builders greatly appreciated.

Thanks

Pat 

 

 

 

[Astrobits]

I live in Somerset and you're welcome to come and see my 16"dob to get some ideas. I am planning to build another dob ( or 2 ) just as soon as I get down to that project on my to-do list.

Nigel

[faulksy]

Get the dob builders Bible. 

And ask as many questions as you like  👍 

[PeterW]

Which Bible, there appear to be two?

Peter

[NGC 1502]

Kriege and Berry book- The Dobsonian Telescope.

Covers everything you need for DIY large Dob build. Includes a section for an 8” solid tube Dob.

 

Edited October 18, 2022 by NGC 1502

[PeterW]

Portable Newtonian Telescopes by Highe is the other notable work. 
Lightweight Giants by Overholt is considered another, but has never been widely available… put foam between plywood for light and stuff construction.

Peter

[NGC 1502]

Good online source-google Stellafane telescope making.  Lots of links to further links. Even if you’re not building a scope it’s a great read.

[faulksy]

13 hours ago, NGC 1502 said:

Kriege and Berry book- The Dobsonian Telescope.

Covers everything you need for DIY large Dob build. Includes a section for an 8” solid tube Dob.

 

This one @PeterW👍

[skybadger]

Timely. 

I'm currently building my own 16" alt az dob which will be an 8 truss construction. Partly from Highe, partly from Stellafane, partly across the web. 

Mine is built from plywood scraps and 3d printings. So I can provide truss clamp and wire tensioner models for printing. 

Hers a pic of the mirror box showing the truss Ball sockets and collimation motor 

Here's a photo of the guitar string wire spider tensioner mount block. 

I have a 15" f/6 to mount on the scope to start with and I need to figure a mostly complete 16" f3.5 as the final configuration. 

happy to chat further if you like and it's helpful. 

 

 

 

 

Edited October 19, 2022 by skybadger
Spellings

[skybadger]

I find K&B a bit old hat now, Highe is much closer to modern and to tell the truth, there's a lot of ATM on Cloudy Nights (gasp!) That's really good. The wire spider threads for example, as too the hexapod focusing and collimating and the use of sling vs supports to keep the mirror centred and unstressed. 

[skybadger]

You've seen this I assume ? https://stargazerslounge.com/topic/293946-16-open-truss-dobsonian-build/?do=getLastComment

[geoflewis]

Each time I see this topic pop up in the list, I think it's going to be about another conservative leadership contest...... 🤣

[faulksy]

On 19/10/2022 at 13:04, skybadger said:

I find K&B a bit old hat now, Highe is much closer to modern and to tell the truth, there's a lot of ATM on Cloudy Nights (gasp!) That's really good. The wire spider threads for example, as too the hexapod focusing and collimating and the use of sling vs supports to keep the mirror centred and unstressed. 

Good as a guide though and add more modern techniques 

[saac]

On 19/10/2022 at 13:05, geoflewis said:

Each time I see this topic pop up in the list, I think it's going to be about another conservative leadership contest...... 🤣

I think we are going to see another truss tube build shortly 🤣   To the OP ( @PatG ) I was going to highly recommend the Moonlite accessories (connectors etc) but I see that they are no longer making them.  Great shame as these not only work really well but also look good.

Jim 

Edited October 20, 2022 by saac

[PatG]

Hi All

Thank you all for your tips, advice and recommendations. some background reading is in order.

This project is a slow burner but if / when I get it underway no doubt I will be reaching out for some more advice.

Pat 

 

 

[markse68]

On 19/10/2022 at 13:00, skybadger said:

Hers a pic of the mirror box showing the truss Ball sockets and collimation motor 

Hi Badger, nice looking build but won’t you need at least 2 collimation motors?

Mark

[skybadger]

Hi mark. The second one is indeed in there now. I was missing a belt of the right length. 

Ready to test. 

The thread for the mirror post is 2mm pitch, the pulley ratio Is 1:3 and the motor is a worm at 2rpm. So I should get 1.33 mm/minute (20 micron a sec) and it stay locked in position once achieved. 

I'll also be using a pwm driver to control the speed if I require more sensitive speeds