Ask A Scientist© Biology Archive

Author:         guest11
Text:           A stage micrometer can be used to measure specimens observed 
under the microscope.  Is this done by measuring the field of view in each 
objective?  And then using these distances to estimate the size of the 
specimen?

Response #:  1 of 1
Author:      moodywj
Text:        Usually a stage micrometer, that is a calibrated set of marks on 
a slide that can be viewed through a microscope, is used to calibrate the 
scale on a micrometer that inserts into the ocular (eyepiece) of the 
microscope.  Then to measure you simply count the divisions in the ocular 
micrometer which are superimposed on your view of the specimen and use the 
calibration factor to calculate the actual dimension.  There are fancy 
(translate expensive) stages that move in calibrated amounts that can do the 
same thing.  You can also make very accurate measurements by making a video 
image and digitizing it for use with computer image analysis software.