Why the object lens is smaller in compound microscope compare to astronomical telescope?
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.
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.
