3B Scientific Binocular Polarization Microscope - Manual (Page 2)

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Condenser: Abbe condenser N.A.1.25 NA 0.65
with iris diaphragm , filter holder and blue filter,
focussed via rack and pinion drive
Dimensions: 240 x 190 x 425 mm³ approx.
Weight: 6 kg approx.
3. Unpacking and assembly
The microscope is packed in a molded styro-
foam container.
• Take the container out of the carton remove
the tape and carefully lift the top half off the
container. Be careful not to let the optical
items (objectives and eyepieces) drop down.
• To avoid condensation on the optical com-
ponents, leave the microscope in the original
packing to allow it to adjust to room tem-
perature.
• Using both hands (one around the pillar and
one around the base), lift the microscope
from the container and put it on a stable desk.
• The objectives will be found within individual
protective vials. Install the objectives into the
microscope nosepiece from the lowest
magnification to the highest, in a clockwise
direction from the rear.
• Put the head onto the top of the stand and
tighten the head-lock-screw. Insert the eye-
pieces into the tube.
• Insert the analyser into the slot on the re-
volving nosepiece.
• Insert the condensor with polariser and tigh-
ten the lock-screw.
4. Operation
4.1 General information
• Set the microscope on a level table.
• Place the object to be observed in the centre
of the specimen stage. Use the clips to fas-
ten it into place.
• Connect the mains cable to the net and turn
on the switch to get the object illuminated.
• Make certain that the specimen is centered
over the opening in the stage.
• Adjust the interpupillary distance so that one
circle of light can be seen.
• Make the necessary eyepiece dioptre ad-
justments to suit your eyes.
• To obtain a high contrast, adjust the back-
ground illumination by means of the iris dia-
phragm and the variable illumination control.
• Rotate the nosepiece until the objective with
the lowest magnification is pointed at the
specimen. There is a definite “click” when
each objective is lined up properly.
NOTE: It is best to begin with the lowest power
objective. This is important to reveal general
structural details with the largest field of view
first. Than you may increase the magnification
as needed to reveal small details.
To determine the magnification at which you are
viewing a specimen, multiply the power of the
eyepiece by the power of the objective.
• Adjust the holding brake to give a suitable
degree of tightness in the focusing mecha-
nism.
• Adjust the coarse-focusing-knob which
moves the stage up until the specimen is fo-
cused. Be careful that the objective does not
make contact with the slide at any time. This
may cause damage to the objective and/or
crack your slide.
• Adjust the fine-focusing-knob to get the im-
age more sharp and more clear.
• Colour filters may be inserted into the filter
holder for definition of specimen parts.
Swing the filter holder out and insert colour
filters.
• Always turn off the light immediately after
use.
• Be careful not to spill any liquids on the mi-
croscope.
• Do not mishandle or impose unnecessary
force on the microscope.
• Do not wipe the optics with your hands.
• Do not attempt to service the microscope
yourself.
4.2 Using the polarisation equipment
• Insert the analyser into the slot on the re-
volving nosepiece.
• Rotate the polariser until the planes of the
polariser and the analyser are exactly crossed,
so that one sees a black background.
Any object with a doubly-refracting (birefringent)
structure should now appear brightly illuminated
against the dark background. If that does not
occur, it is possible that the direction of light
vibration of the object coincides with the polari-
sation direction. Whether or not that is the case
can be tested by rotating the polariser or the
specimen itself.
A birefringent object, when rotated continuously,
shows up brightly after each 90° rotation and is
dark between these positions. In contrast, ob-
jects that are isotropic and not birefringent re-
main dark in all positions.