List of largest optical telescopes in the 18th century

List of largest optical telescopes in the 18th century includes various refractors and reflectors that were active some time between about 1699 to 1801.

Many of the largest were metal mirror reflectors, some of which had substational apertures even for the 20th century.

including William Herschel, did not pass on their mirror-making craft, and by the next century reflectors had largely been passed over in favour of small achromats (2-lens refractors).

The major breakthrough in the 18th century was the perfection of two and even three lens refractor telescopes, as well as the increased number of reflectors using polished metal mirrors rather than metal-coated glass, which was not developed until the mid-19th century.

The list is inherently limited by what examples and records have survived.