In the 17th century, Galileo Galilei pointed the first telescope to the Heavens. In doing so, not only did he provide humanity with an enhancement of the eye, but he completely changed our position in the universe, psychologically and philosophically. Since then, astronomy has continued to change our view of the universe and our relationship to it.
The single most important technological change that has allowed the dramatic increase in astronomical knowledge has been the ability to continue building larger telescopes. The ability of a telescope to resolve two close stars is directly proportional to the wavelength of the light l used for the observations and inversely proportional to the diameter of the telescope D, often expressed as the ratio l∕D. This is why, in order to distinguish between ever closer pairs of stars, or to observe finer details on an astronomical object, the options are to increase the diameter of the telescope or to decrease the wavelength of light. The additional advantage of larger telescopes is that they collect more light on shorter-exposure time scales, improving the view of dimmer objects.
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