And yet another Truss dobson!

[Marijn]

Dear astronomers,

Hereby I would like to present you with my nearly finished Truss dob. It's nothing fancy, just... another Dob;)

The optics come from an Orion OTA ( 8" F5 ).

The telescope is rather large compared to it's optics, but this allows the upper part of the telescope to be placed on top of a lid which covers(and protects) the primary mirror, in case one decides to fold the scope together. Furthermore, the focusser and secondary mirror do not need to be removed to fit into the box.

Ofcourse, the High Gloss knobs used to mount the trusses and Alt-bearings inside the primary mirror box still need to be replaced by something less shiny;)

The azimuth bearing is a roller bearing, actually I bought a small turning-table from IKEA(9 euro's), which seemed to be made for this job!

[Helen]

Oooh, that's lovely!! Have you got any pictures of it during construction?

Helen

[appalachik]

Very nice work Marijn, congratulations

[RikM]

Beautiful scope.

[Gina]

My word, what a lovely job! :) That's really nice - congratulations

I should also add... that's such a very neat way it all folds up and fits in the box. Very impressive!

[asteria]

That is a very nice telescope - thanks for sharing the pictures. Ed

[Pug]

That's really nice, really really nice! You say it's nothing fancy but i would have to disagree, wish i had your talent.

[twotter]

That's a clever idea and looks great!

[swamp thing]

Now that's what I call a Dob.

Simple, elegant, beautiful and well made.

Congratulations.

Regards Steve

[Anweniel]

It's nothing fancy, just... another Dob

I think when the next edit. of the oxford concise is released under the word 'understated' you will find this thread..

That DOB is just genius I love it!

[Moonshane]

superb scope. you obviously did a lot of thinking and planning. beautiful.

[Marijn]

Haha thanks for the nice replies! And believe me, the only thing that makes this thing look fancy is the paint scheme which turned out quite well:)

Hereby I will post some of the drawings I've made(actually it's only 1/3 of the drawings i've made), but they are the only ones which are 'correct'. I don't know if it can be of any help, I accurately designed the primary & secondary cage to fit the optics as well as possible, the rest of the scope has been built around it without drawings.

Secondary cage topview:

Secondary cage sideview:

Primary cage sideview:

Accurate measurements made by measuring up the Orion OTA:

Some helpfull sketches to determine the truss length:

Best regards,

Marijn

[captaincaveman]

amazing work, you should start taking orders:hello2:

[runoffshed]

Fabulous work, Marijn, just stunning.

Can I just ask whether you needed to add any weight to the mirror box end or mirror cell? I only ask as that looks like quite a chunky focuser and yet you still have the balance point quite near the mirror. Also, what's the secondary cage made of?

Any more projects in mind for the future?

All the best

[Marijn]

Well I haven't quite figured out how to keep it balanced. Currently, as it is on the photo's, it's nicely in balance. It still lacks a finderscope/reddot though:icon_confused:, so it will probably need some counterweight. I left some space on the bottom side of the mirror box, to add weight. On the other side.. maybe a spring would work better. I'm still thinking this one over.

The secondary cage, just as the rest of the scope, is made of simple cheap plywood. I used three different strengths: 14mm, 9mm and 3mm for the bent wood inside the secondary cage.

Next projects.. I don't know! Currently I've got 2 dobs, a 6"refractor & a skymax 180, so there's enough to play around with:) On the other side, seeing the end result of this dob just pulls me to keep on building new stuff..

Marijn

[ZEbbEDY]

tidy job man

you could easy sell those

[runoffshed]

Thanks for the info, Marijn, much appreciated. As I said before, stunning scope!

[Moonshane]

I think I'd solve the balance issue with some flat steel triangles fitted into the recess under the mirror box. this should do it. make it slightly bottom heavy as you can easily add a little weight at the top end to sort that out. like a spare set of batteries in your telrad.

[RogerTheDodger]

Beautifully made

[JamesM]

A very well thought out and executed piece of stylish workmanship and certainly elevates the definition of DIY, which is so often characterised as homespun and bereft of any aesthetic consideration.

Thanks for posting, inspirational and raising the bar for us mortals!

James

[Nibor]

A really professional and well presented scope - you must be very pleased with it!!

[Coco]

Bravo... beautiful scope.. you must be very proud.

[Marijn]

Thanks guys, I'm very happy with the scope, and ofcourse I'm eager to try it. Just have to mount the RDF and she's finally ready

Best Regards,

Marijn