A Newtonian telescope on a particular type of altazimuth mounting. The base is a flat board, on which rotates an open-topped box; the altitude axis of the telescope rests in V-shaped cutouts in the sides of the box (see the diagram). An important feature of the design is the use of Teflon pads to provide low-friction bearing surfaces. The design is named after the American amateur astronomer John Lowry Dobson (1915–2014).