omaroo
August 20th, 2008, 02:43 PM
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, I then think "yeahh.....why not!".
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 by 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 the other scope as pictured - and this gave me the basic design principle.
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, I then think "yeahh.....why not!".
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 by 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 the other scope as pictured - and this gave me the basic design principle.