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Microscope
A. The Compound Microscope
The microscope is a delicate, precision instrument. It must be treated gently; the
slightest bump or jar may damage the alignment of its lenses. Carry the microscope with
care by grasping its handle with one hand, keeping the instrument close to your body and
supporting its base with the other hand. Always carry the microscope with two hands.
Microscope lenses are to be cleaned before and after each use with lens paper. Never
wipe a lens with paper toweling, handkerchief, or Kleenex. If you wear corrective
glasses for astigmatism you must use them with the microscope; if your glasses are for
near-sightedness or far-sightedness, you may use the focus of the microscope rather than
your glasses.
Parts of the Compound Microscope
1. The ocular is located at the upper end of the inclined body tube. The ocular contains
two lenses with a total magnification of 10X.
2. The inclined body and the nosepiece hold the ocular lenses and objective lenses at a
set distance from each other. The body stays in place and the stage raised or lowered for
proper focusing).
3. The rotating nosepiece is attached to the lower end of the focusable nosepiece and the
three objective lenses are mounted on the rotating nosepiece. The rotating nosepiece may
be turned to either direction, so the objective may be changed while viewing a specimen,
4. The three objective lenses, so called because they are closest to the object or specimen,
have individual magnifying powers of 4X, 10X, and 40X. The 4X objective lens is called
the low power objective, the 10X objective lens is the medium power objective, and the
40X objective lens is the high power objective. When an objective is placed over the
specimen, the objective lens will produce a magnified image which will be viewed
through, and further magnified by the ocular at the top of the body tube. A combined
magnifying action makes this instrument a compound microscope. The magnifying
power of the ocular multiplies or compounds the magnifying power of the objective. The
total magnification is magnification of the ocular multiplied by the magnification of the
objective, for example on low power the total magnification is 4 x 10 = 40.
5. The mechanical stage is mounted perpendicularly from the arm and below the
nosepiece. This part supports the specimen slide over a hole that admits light for
specimen illumination.
6. The mechanical stage has a spring-clip to hold the specimen slide in place. Two
control knobs move the mechanical stage (and therefore the specimen slide) for viewing.
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