"Refractor" Quotes from Famous Books
... devised by Galileo is called the Refracting Telescope, or "Refractor." As we know it to-day it is the same in principle as his "optick tube," but it is not quite the same in construction. The early object-glass, or large glass at the end, was a single convex lens (see Fig. 8, p. 113, "Galilean"); the modern one is, on the other hand, composed of two lenses ... — Astronomy of To-day - A Popular Introduction in Non-Technical Language • Cecil G. Dolmage |