Galileo's tube spotting scopes

 

— models built according to the scheme of Galileo Galilei.

Such pipes are familiar to many from films about the era of the sailing fleet — they were used by sailors in those days. Technically, this scheme is outdated: it does not provide high magnifications, works at a constant magnification, requires a large focal length (due to which the tubes have a characteristic sliding design) and is inferior to more modern solutions in terms of image quality. Therefore, nowadays, Galileo's pipes are, usually, souvenir items designed for lovers of antiquity, collectors, fans of the sailing fleet, etc. However, such a device can be used for practical purposes, for observations.