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How do telescopes work?



The purpose of a telescope is to make objects that are far away from you appear closer, so you can see them better. You can use a telescope to see the writing on a dime that's 150 feet (55 meters) away from you. Why can't you see the writing at this distance without a telescope? Because the object is so far away, it doesn't take up much room on your retina (the "movie screen" inside your eye). A telescope, however, magnifies the image that you see, so it takes up more room on your retina. A magnifying glass also enlarges an image so that it takes up more room on your retina so you can see it better. The larger the lens or mirror used in a telescope, the more light the telescope can collect. The more light you get, the brighter the image is and the clearer you can see it.