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Who invented the telescope5/28/2023 ![]() ![]() Theįresco by Tomasso da Modena was completed in 1352 (see here). Isnardo clearly showing a reading mirror on the shelf. Concave mirrors (known as reading mirrors) had been usedĪs reading aids in Europe right up to sixteenth century (see University of Arizona). The magnifying effect of concave mirrors was well known to both the Muslim and medievalĮuropean natural philosophers. One design for solar concentrators is the Cassegrain design so popular in astronomy. Solar concentrators and are typically used to generate electricity. To redirect incoming rays to a focus point. Burning mirrors, like reflecting telescopes, would be required To have assembled 'burning mirrors' in Syracusa to set a Roman fleet afire from several That is the date that Archimedes is thought Interest in the use of mirrors to concentrate light dates back to at least 212 BCE. Reflecting Telescopes:A Short Pre-History Spare mirrors would be needed if the telescope was to be used That meant it would need to be removed and repolished (potentiallyĬhanging its shape). Being metal, it expanded andĬontracted much more than glass with temperature changes. It reflected only about two thirds of the light that hit it. Sharpness of existing refracting telescopes.Īnother problem with early reflecting telescopes was the speculum metal itself. Isaac Newton's compromise of using a spherical shape had little hope of matching the circa 1300 ), shaping metal to this precision was something new. Grinding and polishing of glass to create lenses had been practiced for centuries Would require a parabolic or hyperbolic shape. A reflecting telescope that could compete with refracting telescopes The tolerancesįor mirrors is four times more critical than for lenses. Whatever problems refracting telescopes hadĪt the time were small by comparison to those of reflectors. Good enough to be used in telescopes would not be available for another This is an alloy of copper (2 parts) and tin (1 part). spherical, paraboloid).Įarly reflecting telescopes were made from these designs using the speculum metal then usedįor regular mirrors. Several configurations ofĬonvex mirrors ,concave mirrors and lenses were proposed, some of which are still in use today.ĭifferent shapes were suggested for the mirrors (e.g. The reflecting telescope did not have these problems. This could result in fuzzy edges to objects. The problem is that glass refracts theĭifferent wavelengths of light differently, resulting in different focus Light rays at the objective to a single focus point. Interest were some very serious problems with early refracting telescopes. The Jesuit priest, Niccolo Zucchi,Įven built a crude reflecting telescope as early as 1616. Shortly after the invention of refracting telescopes. Interest in the idea of building telescopes using mirrors instead lenses began To the work that preceded them and that was being done by contemporaries. Understanding the contributions of Mersenne, or for that matter Newton, requires some attention Marin Mersenne presented workable designs for reflecting telescopes that are still used today.īut he was not the first to toy with the idea of using mirrors in place of the lenses of the telescope. By coincidence, all three were Roman Catholic priests. TheĮarly proponents of reflecting designs (Marin Mersenne, Bonaventura Cavalieri,LaurentĬassegrain) deserve a closer look. Histories of the reflecting telescope typically skip over theirĬontributions to start with Isaac Newton (1668) or James Gregory (1663). The earliest champions of this design published their designs 30 yearsīefore the debut of Newton's telescope. Over the last 120 years, almost all of the largest optical telescopes were reflecting telescopes The Early Reflecting Telescope:Cassegrain and Mersenne ![]()
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