3B Scientific Binocular Microscope Model 500 with Polarization Equipment - Manual (Page 6)

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Polarisation equipment: Polariser and analyser
Eyepiece: Pair of wide field eyepieces WF 10x 18
mm and WF 15x 13 mm
Objectives: Inverted objective revolver with 4 plan
achromatic objectives 4x / 0.10, 10x / 0.25, 40x /
0.65, 100x / 1.25 (oil)
Magnification: 40x – 1500x
Object stage: x-y cross table, 155 x 145 mm 2 , with
object guide and coaxial adjustment knobs per-
pendicular to the object stage, adjustment range
50 x 76 mm
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Illumination: Adjustable 6 V, 20 W halogen lamp
incorporated into the base, universal 85 to 265 V,
50/60 Hz power supply
Condenser: Abbe condenser N.A.1.25 NA 0.65 with
iris diaphragm , filter holder and blue filter, focus-
sed via rack and pinion drive
Dimensions: 306 x 190 x 407 mm³ approx.
Weight: 6.6 kg approx.
3. Unpacking and assembly
The microscope is packed in a molded styrofoam
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 i-
tems (objectives and eyepieces) drop down.
• To avoid condensation on the optical compo-
nents, leave the microscope in the original pa-
cking to allow it to adjust to room tempera-
ture.
• 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 magni-
fication to the highest, in a clockwise direction
from the rear.
• Put the binocular head onto the top of the
stand and tighten the head-lock-screw. Insert
the eyepieces into the tube.
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 and clamp it to the object
guide.
• 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 adjust-
ments 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 struc-
tural details with the largest field of view first.
Than you may increase the magnification as nee-
ded to reveal small details.
When 100x (oil) objec-
tive is chosen, objective oil must be dripped onto
the slide.
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 mechanism.
• Adjust the coarse-focusing-knob which moves
the stage up until the specimen is focused. Be
careful that the objective does not make con-
tact 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 image
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.
• Use the knobs of the mechanical stage to move
the slide side-, back- and forwards. The vernier
provides accurate location of the specimen
area.
4.2 Using the polarisation equipment
• Insert the analyser into the slot on the revolv-
ing nosepiece.
• Place the polarising filter on the rim aperture
of the light source.
• 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 oc-
cur, it is possible that the direction of light vibra-
tion of the object coincides with the polarisation
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, objects