GEM-mounted 12" truss telescope from a beer keg

[Omaroo]

Righto - call me nuts, but I'm going to give this a go.

I was clearing out my garage the other day and came across an old stainless steel beer keg that's been sitting there for years.

I measured the base of it, and on an inkling I discovered that the internal diameter at the base is 32cm! I look at it again and think "naaaa.....".

I look at it yet again, after some more thinking, and then think "yeahh.....!".

I'm going to part it off at the "1" and "2" marks. I'll toss the top away. The ribbed center section will become the centre of my truss OTA - where I connect my dovetail to. It will have short trusses going back to the rear section to hold the mirror "cell", and another set going forward to hold the to-be-constructed secondary cage.

The rear cell will be cut out where the black sections are to lighten the structure. The steel is strong and not particularly heavy once it's all cut out. The three newly-formed "arms" around the centre of the rear cell will have the collimation nuts welded to them at 60% of the mirror radius. I'll also cut out the center and mount the fan. The perpiheral area will also be lightened bu cutting plenty of large holes. A good polish or powder-coat and it'll look great I reckon. It's actually beautifully constructed and fits the purpose very well.

Until I get around to completing my bino, I have two Suchting DSO 12" f/5's sitting on my shelf looking bored. Neither has seen first light, and this may be just the ticket.

It'll be interesting either way!

I've always liked mhc62's scope as pictured - and this gave me the basic design principle.

[Jone5y]

Let's see here.... Beer, Aperture, a big DIY project and 2(!!!) Suchting mirrors.

What more could an astronomer want? Perhaps some extra time to construct the Bino.

Sounds like a great project, be sure to keep us jealous ones informed.

Steve.

[Ian Robinson]

He'll have to empty another keg to do that .... some of his IIS mates would probably be more than willing to assist him with if he asks them nicely.

[Omaroo]

Beer gone.

Keg empty.

De-pressurised.

Void.

Keg now available to make telescope or BBQ.

Me choose telescope. Silly, I know!

[gbeal]

I'll play your game, you're nuts.
I built mine from ply and some CF tubing.
Got thirsty doing it though, so maybe I should have used your idea after all.
Gary

[CoombellKid]

The top bit you throw away... why not flip it attach some legs add a
grill on top... and wolah!!! bbq.... nice size for bacon and eggs after
a long hard night at the eyepiece :thumbsup:.

regards,CS

[Omaroo]

You're following me Gary... beer and nuts. :thumbsup:

I've just been measuring up and marking out the cutouts in the rear cell. The more I look at it the more I like the idea of it. The greatest thing about it is that the mirror box and "tailgate" as such are one homogenous piece. What I don't like about it is that this much SS is going to be an absolute bugger to cut given home workshop tools.

CS - hmm.. waste-not, want-not hey? Good idea - a hibachi :D

[bmitchell82]

if it is going to be a real hard slog cutting it out, you could always see if a machine shop will cut it out for you with a plasma cutter.... those things work though metal like a hot knife though butter! food for thought.

The bbq idea is winning votes for the left overs! :D spud chippies for the haul though the night and then bacon and eggs to recover! :D

[AlexN]

Oh how I wish I could build myself a truss 12" for my EQ6..

Looks like a nice plan indeed...

Whats the weight going be like with that much SS??

[Omaroo]

Hi Alex

Don't know yet. I guess that it's a wait and see exercise. There's lots of weight that can be cut out of the structure because it's so inherently strong. The heaviest part is the curled-over steel rim - which can also be removed if absolutely necessary. I'll keep it all there until I get the whole thing assembled, and then I'll see where the balance point is going to be and go from there.

Brendan - thanks for that - top idea. I'll start looking for a local shop that has a plasma torch.

[AlexN]

oh true, I should have thought of that... You wont have to keep it as a full tube section... being SS you could probably remove over 50% of it and still retain its rigidity.. I'd be removing triangle sections if it were me...