Small reflecting telescope, after J. Gregory (1663)

This small reflecting telescope was made after the design of the Scottish astronomer and mathematician James Gregory. In 1663 he devised the reflecting telescope to circumvent the problem of chromatic dispersion, which is caused by using lenses. Not until the beginning of the eighteenth century it turned out to be technically possible to realise the design. That is why the English physicist Isaac Newton devised a simpler model with one bent and one flat mirror. His model was also very difficult to copy for other people. Not until the eighteenth century, when the raw materials and the skills for making mirrors were greatly improved, the reflecting telescope became really popular. This specific telescope is still in working order, but gives a yellowish tinge to the image. Just like all small reflecting telescopes, it can be used as a microscope.