What is a scaled reticle?

A reticle is a clear glass disc marked with scales or patterns that is placed in a microscope eyepiece at a particular position that superimposes the pattern with the image viewed through the microscope. A scaled reticle is a microscope eyepiece reticle designed to be accurate for a specific objective magnification. Most reticles are specified for a 1X magnification and are not scaled for the objective power of any particular microscope, making a conversion factor necessary. Stage micrometer scales are designed for not only calibrating microscope eyepiece reticles and objective powers, but also for determining the conversion factor from an eyepiece reticle scale designed at 1X to the true measurement as objectives, eyepieces, or reticles are interchanged. Stage micrometers are placed on the microscope stage and are similar in format to microscope slides. Please note that for a zoom microscope the reticle is only scaled at one objective power position. In this case, repeating the scaled position may be difficult.