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A one Dollar Compound Microscope |
 | | These objectives originally were designed in such a way that the chromatic defect produced by the first lens was compensated by the opposite defect produced by the second lens, with the result that the various colors were focused at the same distance thereby producing a sharper image. |
| | Usually, these lenses are cemented together in pairs (doublets) for the correction of the red and blue colors (achromatic lenses) or in groups of three (triplets) to obtain a chromatic correction that is even better for each of the three primary colors: red, green, blue (apochromatic lenses). |
| | With normal lenses (non achromatic) you can obtain fairly good images as long as you limit yourself to moderate magnifications, whereas for high magnifications the use of achromatic lenses in the objectives becomes necessary. |
| www.funsci.com /fun3_en/ucomp1/ucomp1.htm (7494 words) |
