Galileo's first telescopes

Hans Lippershey, a Dutch spectacle maker, was watching two children in his shop playing with lenses. When the children looked through two lenses, a weather vane on a nearby church appeared both larger and clearer. Lippershey tried it himself, and then placed a tube between the lenses to make the first telescope. And the rest is history. Lippershey apparently carried a letter from the government of Zeeland to its delegation to the States General of the Netherlands on September 28, 1608 asking for help to the bearer "who claims to have a certain device by means of which all things at a very great distance can be seen as if they were nearby, by looking through glasses which he claims to be a new invention.". This is the earliest record of the device which we now call the telescope.

The Belgian government found the device too easy to copy to award a patent, and its new spread rapidly throughout Europe. By 1609 spectacle makers in Paris and Italy were making three-powered spyglasses, but it was Galileo who made the instrument famous. He built his first three-powered telescope in June or July of 1609, and later that same year made telescopes that could magnify 8, 14 and 20 times. In October or November of 1609 he turned his 20X telescope on the Moon, discovered the four satellites of Jupiter that bear his name, and resolved celestial nebulae, or clouds, into their component stars.

When Galileo first saw Saturn through his 2" telescope in 1610, it appeared to him either as if the planet had "ears," or that it was three separate objects, both interpretations due to the smallness of his scope and its optical imperfections. Galileo had already constructed 60 telescopes by the time he published Sidereus Nuncius in 1610. Most of these were intended as gifts, Galileo himself making only the lenses, while the tubes were built locally to his specifications. Of these instruments only two survive, of 14X and 21X (magnification) respectively, and from 1" to 2" in diameter. Although the glass had bubbles and suffered from cosmetic defects, the many world-famous experts (Ronchi, George Ellery Hale and Giorgio Abetti) who later examined these earliest of telescope optics claimed that their quality was excellent.

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