Early Designs
Despite the fact that the Cooke design was patented in 1893 it seems that the use of achromatic triplet designs in astronomy appeared as early as 1765. The 1911 Encyclopædia Britannica wrote:
- The triple object-glass, consisting of a combination of two convex lenses of crown glass with a concave flint lens between them, was introduced in 1765 by Peter, son of, John Dollond, and many excellent telescopes of this kind were made by him.
This parallels the fact that John Dollond had in turn patented the achromatic doublet in the 1750s, though it had been used decades earlier.
Read more about this topic: Cooke Triplet
Famous quotes containing the words early and/or designs:
“To be candid, in Middlemarch phraseology, meant, to use an early opportunity of letting your friends know that you did not take a cheerful view of their capacity, their conduct, or their position; and a robust candour never waited to be asked for its opinion.”
—George Eliot [Mary Ann (or Marian)
“I have no scheme about it,—no designs on men at all; and, if I had, my mode would be to tempt them with the fruit, and not with the manure. To what end do I lead a simple life at all, pray? That I may teach others to simplify their lives?—and so all our lives be simplified merely, like an algebraic formula? Or not, rather, that I may make use of the ground I have cleared, to live more worthily and profitably?”
—Henry David Thoreau (1817–1862)