Care and Use of the
Compound Microscopes
Moorpark College Biology
Department
Care and Use of the Compound
Microscopes
• Ten things to consider when storing a
microscope
• How to adjust the microscope for your
eyes
• Tips on the microscope
Ten things to consider when storing
a microscope
• These ten items for consideration are not
in any order or importance or sequence.
• These are the minimal steps to take care
of our microscopes, which are excellent
when they are well cared for.
• Think of your use of the microscope as a
new professional skill.
#1 Remove slides from stage
• #1 Remove slides from stage.
– Be sure to place the prepared slides in their
correct tray. Look at the label of the slide and
the label of the edge of the tray. Viola!
– Wet mounts should be rinsed by you and the
cover slips and slides placed in the labeled
beakers.
#2 Rheostat set to lowest level
• #2 Rheostat (or power level) is set at zero
or lowest setting.
• Why?
– If the microscope is turned on with the
rheostat at the highest level a surge of energy
can blow the light bulb.
– Bulbs cost $25 each!
#3 Store the microscope in it’s
proper cabinet
• #3 Put the microscope in its proper
cabinet. The number on the bottom of the
arm will have a room and cabinet number
(220-52, for room LMC 220 and cabinet
52).
• Why is this important?
– To keep track of the microscopes, to
determine which are being repaired or
borrowed and not stolen! Always place it in
the correct cabinet.
#4 Cover
• #4 Cover with a plastic bag or cover.
• Why?
– To protect it from dust. These are very
expensive and sensitive pieces of equipment
and we want them to work well for you.
#5 Clean the Microscope
• #5 Clean the Microscope
• How?
– Lens paper and glass cleaners for the lenses
only! Don’t forget the eyepieces, too. Although
oil should only be used with the 100X
objective it often gets onto the 40X objective
lens and stage as well.
– Kim wipes can be used to clean the stage and
other parts of the microscope.
#6 Power is off
• #6 Power is off.
• Why is this important?
If someone plugs in the microscope the
and the power is on the surge of electricity
can blow-out the halogen lamp. Each lamp
cost more than $25!
#7 Lowest power objective
• #7 Lowest power objective in place.
• Why? One reason is to prevent the stage
from accidentally crashing into the
objective lens. The other reason is that
when you begin to use the microscope you
must (should) always start with the lowest
magnification. This is the best technique
and prevents lens damage.
#8 Arm facing out
• #8 Place microscope in cabinet with arm
facing out.
• Why?
– So that the next student can easily remove it
from the cupboard.
– Also the head piece of the microscope can be
loosened and if the microscope is placed in
the cupboard backwards it may be grabbed
by the headpiece and the bottom dropped!
#9 Wrap power cord
• #9 Wrap power cord around the base of
the microscope.
• Tip. Don’t wrap it too tight! The wire inside
the power cord can break inside the plastic
covering if it is stressed too much.
#10 Lock it up
• #10 Lock it up.
• Why? We don’t want to lose them, they’re
very expensive.
• Don’t forget to return the key to the front of
the room or lab cart. If you discover you
accidentally pocketed the key – just bring
it back ASAP.
How to adjust the microscope for
your eyes
• If the microscope is not adjusted for your
eyes, your brain will try to merge the two
images, which may result in a headache or
dizziness.
• Remove glasses and adjust the
microscope for your eyes without them,
then:
– Adjust for interpupillary distance
– Adjust for diopter
Adjust for interpupillary distance
• After a slide is focused at a low setting relax at a
comfortable distance from the eyepieces.
• Move the ocular lenses together and apart until
one clear image merges together.
• Note your interpupillary distance on the
microscope. Refocus and readjust for the
diopter.
• Don’t forget to continue to readjust this distance.
Adjust for diopter
• This will let you adjust the microscope for your
two eyes.
– Focus the microscope on a specimen.
– Cover the left eye and adjust the fine focus knob on
one spot in the field of view.
– Cover the right eye and turn the left ocular lens until
the same spot in the field of view is in sharp focus.
– Observe with both eyes, adjust interpupillary distance
until one clear image merges together.
Microscope use tips
• Always change the objective lenses by the
knurled nose ring. When the objective
lenses are used to change power, they are
ever so slightly loosening and damaging
their thread mounts. To work their best all
lenses must be aligned perfectly.
Microscope use tips
• Always begin examining a new slide at the
lowest power possible.
• Use the course focus knob only with the
4X objective lens to get the first level of
focus, then only use the fine focus knob
with the higher power lenses. The working
distance is so tiny it is very easy to scratch
a lens and break a slide at the same time.