Folding DOB

I've been thinking about building a long-focus DOB, something on the order of a 10" f/7. I don't have a beast of a vehicle to haul a tube that long, so it seemed I would have to build a truss DOB.

However, the design shown in ad #242561 under "Telescopes - Reflectors" seems like a neat way to avoid the expense and effort (both building and assembling) associated with a truss structure. I don't really care if this thing packs up into the smallest possible package. I just want it to fit in an ordinary sedan and be easy to set up. I'd guess that making the balance work out is the trickiest part of the deal with a longer tube up top (tube weighs more than a truss, I'd guess). Can anyone else think of problems to watch out for on a project like this?

I can only fit a tube of about 50" in the back seat of my current vehicle. I already own a 6" f/8 tube dob that's in that category, and it can be awkward to use. I like straight-through zero-power finders such as the Telrad, and finding things near the zenith can hurt the neck. I find longer DOBs more comfortable to use (plus they have the added benefit of being more forgiving when collimating).

Thanks for your thoughts.

Duane Jacobson

Thanks for all of the comments. I'll look here for pics of the new 10" f/5.6.

Sofjan... I've thought about doing a split tube. However, having never seen one, or known anybody who uses one, I had always guessed there must be a reason for not doing this. Do you know anybody who has done this?

Truss scopes are certainly much more expensive. It's often difficult to do a real apples-apples comparison, but I looked at Discovery's prices, and see that their 12.5" truss scope is 60% more expensive than their 12.5" tube scope. Of course, that makes sense, as there are many more parts to buy or build, and assemble, when manufacturing a truss scope.

This folding tube scope really looks like a good design to me. It's very simple to assemble, and should be much cheaper to build than a truss scope.

Thanks again,

Duane Jacobson

Brian... that scope looks very much like what I had in mind. Thanks.

And thanks, Sofjan, for the pointer on the 8" travel scope. I'll have to look for that article.

Regards,

Duane