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Truss Tube Dobsonian Telescopes - collapsible Dobs

Scroll down for our offerings of truss tube Dobsonians. 

The king of visual astronomy is the Dobsonian because its design allows for large apertures. And for every inch of aperture, there is an exponential jump in light gathering ability. So, clearly, there is a desire to keep making bigger and bigger scopes. The problem is that, at about 10 inches and up, they become nearly impossible to lug around. 

If you want a giant telescope but also want a prayer of ever transporting it to a dark spot, take a look at the truss tube Dobsonian design. So what is a truss tube Dobsonian?

A truss tube Dobsonian is like any other Dobsonian telescope, except that, rather than a solid optical tube, a set of truss tube supports connect a “rocker box” containing the primary mirror to a cage containing the secondary mirror and focuser. This allows for very large, portable telescopes.

A portable Dobsonian - how it works

Modern truss tube designs are very quick and easy to use. For example, the Explore Scientific - Generation II Truss Tube Dobsonian (pictured right) uses four truss tube pairs, each of which has a groove on each end that slips into a slot, where a couple turns of a knob firmly secures it. Taking it apart is just a matter of loosening the knobs. 

The whole assembly isn’t necessarily lighter than it would be with a solid tube, but each individual piece is certainly lighter and smaller. This can sometimes be the difference between fitting it in the car or not. Or the difference between lifting it or not. 

Flextube design - a collapsible Dob

A very interesting cousin to the truss tube design is Sky-Watcher’s flextube Dob. Instead of truss tubes that completely detach during disassembly, the flextube design features tubes that extend and collapse. You don’t get the benefit of breaking the OTA into two pieces, but when the tube is collapsed, it is definitely more portable. Plus, some people find the sliding feature more convenient. 

Truss tube Dobsonian shrouds

It might be hard to imagine that a telescope could work without a solid tube keeping stray light out. The truth is they work very well. Still, you can purchase a cloth shroud for just about every truss tube Dob. This keeps out stray light and protects the mirror from dust.

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Sky-Watcher Classic 200P 8" Dobsonian Telescope