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Earth to the Moon | Jules Verne | |
THE TELESCOPE OF THE ROCKY MOUNTAINS |
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On the 20th of October in the preceding year, after the close of the subscription, the president of the Gun Club had credited the Observatory of Cambridge with the necessary sums for the construction of a gigantic optical instrument. This instrument was designed for the purpose of rendering visible on the surface of the moon any object exceeding nine feet in diameter. At the period when the Gun Club essayed their great experiment, such instruments had reached a high degree of perfection, and produced some magnificent results. Two telescopes in particular, at this time, were possessed of remarkable power and of gigantic dimensions. The first, constructed by Herschel, was thirty-six feet in length, and had an object-glass of four feet six inches; it possessed a magnifying power of 6,000. The second was raised in Ireland, in Parsonstown Park, and belongs to Lord Rosse. The length of this tube is forty-eight feet, and the diameter of its object-glass six feet; it magnifies 6,400 times, and required an immense erection of brick work and masonry for the purpose of working it, its weight being twelve and a half tons. Still, despite these colossal dimensions, the actual enlargements scarcely exceeded 6,000 times in round numbers; consequently, the moon was brought within no nearer an apparent distance than thirty-nine miles; and objects of less than sixty feet in diameter, unless they were of very considerable length, were still imperceptible. In the present case, dealing with a projectile nine feet in diameter and fifteen feet long, it became necessary to bring the moon within an apparent distance of five miles at most; and for that purpose to establish a magnifying power of 48,000 times. Such was the question proposed to the Observatory of Cambridge, There was no lack of funds; the difficulty was purely one of construction. |
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Earth to the Moon Jules Verne |
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