10" scopes are really not big or unweildly enough to justify a truss configuration. Regardless of whether or not it makes sense, I built this scope with two purposes in mind.
A truss arrangement, when broken down, is more compact. It takes up much less space in the back of a pick up than a 10" tube Dob on camping or star party trips. The various components are small enough to slip into nooks and crannys amoung the sleeping bags, tents, stove, cooler etc. The truss scope is also significantly lighter. Total weight of this scope is 30lbs. Despite being 20lbs, lighter than the sonotube scope it replaced it's lower center of gravity makes it more stable and it's motions feel smoother. The scope retains collimation from day to day and the mirror cools faster than it did with the sonotube model.
The other reason I built this scope was to develop a design that allowed all of the critcal components contained in the mirror box to be small enough to comply as carry on luggage.
I've had some folks ask about the bottom clamps. They are 1" square tubing. As you can see they have a hole drilled for the trusses and another for the knob. You might not see the relief cut from the truss hole to the end of the square tubing on the knob side so it can pinch. Also the clamps come off the box and stay with the truss by a flat spring type hose clamp around the truss inside the square tubing. This keeps the clamp from being loose and also gives an index point for the truss length when reinstalling.
Things I would do different. Avoid the mirror box cutouts in the current design. The UTA could be a section of sonotube, like Paul Lefevre's 8" travel scope. Then the UTA could fit inside the mirror box without the cutouts. Or the mirror box could be built shorter without the cutouts and a single ring UTA attached to the top of the lid for stowing. I favor the second but either method would be a better solution.
The design of this scope borrowed heavily from Tom Krajci's 16" Dob which appeared in S&T a while ago. Check it out!
