ABSTRACT
The top-end equipment is often hand-crafted in the county of design but where there is potential for economy of scale, component manufacture is moved to the Far East. These components mostly comprise optical cells, castings, turned metal parts and labor-intensive assembly operations. Cost-conscious designs often target the unexciting tripod for compromise. Light-weight models packaged with a mount benefit from upgrading: there are several companies that make piers and tripods supplied with adaptor plates to suit the popular mounts. The image planes of a telescope an imaginary surface upon which the stars come to focus. Ideally, this should be flat and coincident with the imaging sensor. The Schmidt Newtonian design addresses some of these limitations. It has a sealed tube with a glass corrector element at the front upon which the secondary mirror is mounted. Advanced folded telescope designs were once very expensive but since Meade and Celestron led the way with affordable designs. The optical tube assembly is very compact.
