Galileo Galilei; a new vision of the universe
Galileo Galilei; a new vision of the universe
Galileo has related how, in 1609, he received a report from abroad on the construction of a spyglass and applied himself to the invention of a similar instrument. "First," he wrote, "I prepared a tube of lead, at the ends of which I fitted two glass lenses, both plane on one side while on the other side one was spherically convex and the other concave. Then placing my eye near the concave lens, I perceived objects three times closer and nine times larger than when seen with the naked eye. Next I constructed another one... Finally, sparing neither labour or expense, I succeeded in constructing for myself so excellent an instrument that objects appeared nearly 1,000 times larger and over thirty times closer than when regarded with our natural vision."
Galileo eventually built hundreds of telescopes (left, two of these now in the History of Science Museum in Florence). His telescope was to bring a new vision to man, though not until intense resistance had been overcome. "My dear Kepler," wrote Galileo to his friend, the German astronomer, "what would you say of the learned here, who, replete with the pertinacity of the asp, have steadfastly refused to cast a glance through the telescope? Shall we laugh, or shall we cry?"