Instead of the usual large circular trunnion bearings riding on a few Teflon pads in the semi-circular cutouts in the altazimuth base, the GSO Dobsonian Telescope uses innovative sealed metal ball-bearing systems to provide smooth vertical motion of the optical tube.
The aluminum bearing housings fit snugly into cutouts in the sides of the altazimuth base. Because the bearings are sealed systems, the elements cannot affect the smoothness of the vertical motion, as it can when dust and grit invariably get trapped between the exposed trunnions and Teflon pads of conventional Dobsonians and scores the surfaces.
The vertical motion of the GSO tube is consistently ball-bearing smooth. And the sealed ball-bearings will not have to be replaced regularly, as is the case with the Teflon pads of many Dobsonians when wind-borne grit degrades the Teflon/trunnion interface.
Manufacturers & Suppliers of Astronomical Telescopes Since 1976