MA254 Walton & Beckett Reticle, 19MM. 0.50” divided into 50 units, 19mm diameter. The Walton & Beckett reticle is used for counting fibrous dust such as asbestos or glass fibers, and is particularly useful where the majority of fibers to be counted are shorter than 5 microns. The circle is divided into four by two diametrical lines scaled in units of 5 and 3 microns respectively. Three and five microns are the critical measurements of fiber lengths and diameter used in fiber counting. Unlike typical globe reticles, the Walton & Beckett reticle has a series of shapes to compare objects with. These shapes have been designed for comparison with fibers, especially since they incorporate an aspect ration of 3:1 or 5:1 essential for analysis. Reticle is available in 19 or 21mm diameters.

The micrometer is mounted in one of the two eyepieces and superimposes an image of the markings over the image of the specimen. Stage micrometers are slides with markings of a known dimension that, when viewed under the microscope, can be used to calibrate eyepiece micrometers. Eyepiece micrometer, cross-line reticle, 19mm diameter

Since the size of the eyepiece micrometer image (e.g. a linear scale) appears the same even though the specimen can be magnified to a greater or lesser degree, the markings on the micrometer do not by themselves indicate any particular measurement. When a stage micrometer with known dimensions is viewed through an eyepiece micrometer, however, the measurement indicated by the eyepiece micrometer at that magnification can be noted and later used to make accurate measurements.microscope micrometer

Dimensions given are the actual size of the markings on the micrometer disc. Eyepieces for our various models require micrometers of different diameter. The model numbers listed below refer to microscopes with standard 10x eyepieces. If you are using optional eyepieces of a different magnification and do not see them listed, contact us to find out the correct size.