Ocular micrometer

An ocular micrometer or eyepiece micrometer is a glass disk, engraved with a ruled scale, that fits in an eyepiece of a microscope,[1][2] which is used to measure the size of microscopic objects through magnification under a microscope.

When the eyepiece micrometer is calibrated using a stage micrometer, the length of the divisions on the scale depends on the degree of magnification.

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