The Differences Between Microscopes and Telescopes
- Although both instruments magnify objects so that the human eye can see them, a microscope looks at things very near, while telescopes view things very far away. Microscopes are commonly found in laboratories, often used by biologists and chemists, while telescopes are found in observatories, most often used by astronomers.
- Although both instruments use lenses to magnify objects, the construction differs from one to the other. One of those differences is focal length. Amazing-space.stsci.edu defines focal length as "the distance between the center of a convex lens or a concave mirror and the focal point of the lens or mirror --- the point where parallel rays of light meet, or converge." A telescope has objective lenses producing long focal lengths, while a microscope has objective lenses producing short focal lengths.
Since telescopes view large objects -- faraway objects, planets or other astronomical bodies -- its objective lens produces a smaller version of the actual image. On the other hand, microscopes view very small objects, and its objective lens produces a larger version of the actual image. The focal lengths of both instruments make this possible. - Another major difference between telescopes and microscopes is the diameter of the lenses. A lens with a larger diameter can absorb lots of light, illuminating the object being viewed. Since objects viewed in a telescope are far away, there is no way for the user to illuminate the object, thus the telescope requires a larger lens diameter. Most microscopes come standard with an artificial light source, illuminating objects. This eliminates the need for a larger diameter lens.
- In telescopes, you can change the eyepiece to modify image magnification, as well as style; the objective lens remains fixed. Alternatively, microscopes have fixed eyepieces and a set of three to four interchangeable objective lenses that you can set differently, changing the magnification and quality of the object.