achromatic telescope

A telescope which minimizes chromatic aberration by means of compound glass lenses (Crown Glass and Flint Glass) with different colour dispersion.

Since Isaac Newton’s discovery of the principle of dispersion (the diffraction of light into different colours when it passes through glass), telescope makers had sought ways of minimizing the diffraction of light. One such solution was to combine glass lenses with different diffraction properties.

Chester Moore Hall had some initial success with this principle. Leonhard Euler discussed the problem in one of his works in 1747. However, the first to achieve commercial success was the English optician John Dollond, who began producing achromatic telescopes in the 1750s.

Cite as: achromatic telescope. In: Travel Reports of a Pioneer: Digital Edition of the Travel Journals of Johann Conrad Fischer 1794–1851. Published by Franziska Eggimann. Edited by Franziska Eggimann, Nicolau Lutz, Valerija Rukavina und Christopher Zoller-Blundell. Schlatt 2023, Version 1.2, https://johannconradfischer.com/en/keywords/gfa-keywords-8431, viewed on 7 July 2025.