Stage Micrometer Available

NAMA maintains a stage micrometer for use in calibrating the eyepiece reticles of compound microscopes. It is available for you to borrow if you are a NAMA member.

Spore size is often an important character used for identifying mushrooms with confidence. A ruler is not useful when it comes to measuring these tiny structures, but a microscope used in conjunction with an eyepiece reticle will do the trick. An eyepiece reticle is a relatively inexpensive circular piece of glass or plastic marked with finely marked graduations that fits in the eyepiece of a microscope. With the reticle in place, un-numbered graduations appear to be superimposed on whatever you happen to be observing through the scope. The distance between the graduations is what a stage micrometer helps you figure out.

The stage micrometer is a finely graduated, numbered scale attached to a standard microscope slide. In our case, the graduations are .01mm (10 microns) apart. You simply put the slide under your microscope and use it to measure the distances between the graduations of your reticle for each objective lens. You need the stage micrometer only once (that's why it's expensive to buy one yourself) to calibrate your eyepiece reticle at each power setting on your scope.

If you want to borrow the stage micrometer, submit your request to the NAMA Executive Secretary. You will be responsible only for return postage and insurance at the $50.00 level. Complete instructions are included.