A 100mm Reflector in the Hands of a Young Astronomer

Abstract

I made the telescope shown in Fig. 6.1, with the help of my dad, when I was ten years old. It is a 100mm (4-inch) f/5.4 Newtonian on a simple altazimuth mount. The mirrors are mounted in a square plywood tube that has altitude bearings, cut from a plastic chopping-board, on the sides. These bearings sit on blocks of Teflon in the semicircular cut-outs in the mount. These bearings are very smooth, so I use half a clothes-peg as a wedge to adjust the friction. The mount rides on plastic and Teflon bearings on a tripod plate from another telescope. The friction is adjusted by tightening the bolt which holds them together. The tripod legs are lengths of 50 × 25mm (2 × 1-inch) softwood. They have central wooden braces which are hinged to the legs and are connected together with an M6 carriage bolt. This tripod is much sturdier than the one which originally came with the tripod plate.