Aperture: 10 inches
Focal Length: 1,270mm (f/5)
Supplier: Telescope House
Telephone: 01892 550100
Although a telescope’s tube is its largest single component, manufacturers of large aperture Dobsonians like to get rid of it.
Instead of the tube, lightweight tubular bars connect the primary mirror and altitude axis at the base of the telescope to the secondary mirror and focuser at the top.
These so-called truss-tube Dobsonians can be broken down into very manageable sections, so that instruments of 18-inch aperture and more can be carried in a family estate car.
Staggeringly small Just as we were going to press last month, we got hold of a 10-inch truss-tube Dobsonian from the Meade LightBridge range.
When we signed for delivery, we were staggered by how small its cardboard box was for its aperture: it packs away to just 77 x 46 x 44cm (30 x 18 x 17-inches).
It’s quick and easy to put the LightBridge together, thanks to the clever design of the three 60cm long (24-inch) A-frame truss sections.
The connecting system on the primary mirror section and the upper section of the tube makes the setup extremely rigid. In three separate sessions of transporting and reassembling the scope, we found that collimation was essentially unaffected.
When assembled, the base of the scope is squat: the altitude axis is just 45cm (18 inches) from the ground.
The eyepiece height varies between 65cm (26 inches) at the horizon to 124cm (49 inches) at the zenith.
The f/5 optics were on a par with the Revelation 10 Dobsonian from Telescope House, a scope with very similar Crayford focuser and mirror cells to the LightBridge.
A superior reflex finder compliments the 2-inch 26mm QX Wide Angle eyepiece (see Group test, November 2005, p97), with its crisp 1.4° field.
All in all, these optics deliver a solid performance from an instrument that’s very striking.