Object-micrometer OMO is purposed for reflected light. It serves to determine an objective magnification, microscope linear field of view, scale factor of eyepiece grids and scales, and to determine an image magnification factor on micro photographs.
The object micrometer is a chromed glass plate with 1mm long scale having 0.01mm scale factor.
This glass plate with the scale is glued into the steel holder having dimensions of usual microscope slide.
To determine a magnification, it is necessary to compare number of the scale steps in the microscope image of the object-micrometer with number of the scale steps in the eyepiece grid or in the eyepiece-micrometer.
Micro picture factor is determined by measuring distance between scale steps of the pictured object-micrometer.
The scale length - 1mm Number of the scale steps - 100 Scale factor - 0.01mm Dimensions: length - 76mm width - 26mm height - 2mm weight - 0.03kg
This object-micrometer is either used, or just got some scratches during moving without container. So, mirror surface isn't perfect, but it is still usable for work without any issues.