63. Microscopio monocular compuesto. R & J Beck. Londres.

Compound monocular microscope. R&J Beck. London.

Compound microscopes produce an enlarged image by means of two optical systems, each consisting of one or more lenses. These act successively. It differs from a simple microscope or magnifying glass in that it magnifies the object through a single optical system (generally a single lens).

Compound microscopes are used to obtain large magnifications, between 40 and 1,500 times of a transparent object. This is illuminated from the other side, against the light (transparent illumination). The total magnification of an observation is obtained by multiplying that of the objective by that of the eyepiece. For example, with a 100X objective and a 15X eyepiece, we get a magnification of 1,500x (1,500X). This is, by the way, the maximum achievable magnification, given the resolution limitations of the lenses.

A typical compound microscope consists of optical elements, which are the fundamental ones, and the mechanical ones. The optical elements serve to form the image and to illuminate the sample. Mechanical elements control the distance from the objective to the specimen (focus). On the other hand, they intervene in the movement of the sample, located on the stage in front of the objective. There are also mechanical elements involved in adjusting the lighting of the sample. Finally, there is the foot or stand that provides stability to the microscope.