In the 1960's, American amateur astronomer, John Dobson, designed a revolutionary kind of astronomical telescope featuring a lightweight large-aperture reflecting system on a simple mounting, using the then-revolutionary material called teflon. The design combines simplicity and portability with large-aperture prowess. Thirty years later Dobsonians remain supreme for visually observing faint deep-sky objects and are one of the best-selling large telescopes in the USA and Europe. This popularity is reflected in the recent increase of companies now heavily marketing Dobsonians, in particular,...