It is not improbable that different persons about Middleburgh hit upon the invention, in different modes, about the same time. Lippersheim seems to have made his first rude telescope by adjusting two glasses on a board, and supporting them on brass circles.[18] Other workmen, particularly Metius and Jansen, in emulation of each other, seem to have made use of that discovery, and by the new form they gave it, made all the honour of it their own. One of them, considering the effects of light as injurious to distinctness, placed the glasses in a tube blackened within. The other, still more cautious, placed the same glasses within tubes capable of sliding one in another, both to vary the prospects, by lengthening the instrument, according to the pleasure of the observer, and to render it portable and commodious. Thus, it is probable that different persons had a share in the invention, and jointly contributed to its improvement. At any rate, it is undoubtedly to the Dutch that we owe the original invention. The first telescope made by Jansen, did not exceed fifteen or sixteen inches in length, and therefore its magnifying power could not have been very great.
The famous Galileo has frequently been supposed to have been the inventor of the telescope, but he acknowledges that he had not the honour of being the original inventor, having first learned from a German, that such an instrument had already been made; although, from his own account, it appears that he had actually re-invented this instrument. The following is the account, in his own words, of the circumstances which led him to construct a telescope. ‘Nearly ten months ago (namely in April or May 1609) it was reported that a certain Dutchman had made a perspective through which many distant objects appeared distinct as if they were near: several effects of this wonderful instrument were reported, which some believed and others denied: but, having it confirmed to me a few days after by a letter from the noble John Badoverie, at Paris, I applied myself to consider the reason of it, and by what means I might contrive a similar instrument, which I afterwards attained to by the doctrine of refractions. And, first, I prepared a leaden tube, to whose extremities I fitted two spectacle-glasses, both of them plain on one side, and on the other side, one of them was spherically convex, and the other concave. Then applying my eye to the concave, I saw objects appear pretty large and pretty near me. They appeared three times nearer and nine times larger in surface than to the naked eye: and soon after I made another, which represented objects about sixty times larger, and eight times nearer; and, at last, having spared no labour nor expense, I made an instrument so excellent, as to show things almost a thousand times larger, and above thirty times nearer, than to the naked eye.’ In another part of his writings, Galileo informs us that ‘he was at Venice when he heard of Prince Maurice’s instrument, but nothing of its construction; that the first night, after he returned to Padua, he solved the problem, and made his instrument the next day; and soon after, presented it to the Doge at Venice, who, to do him honour for his grand invention, gave him the ducal letters which settled him for life in his lectureship at Padua; and the Republic, on the twenty-fifth of August in the same year (1610) more than tripled his salary as professor.’