Adjusting The Aperture Diaphragm(Transmitted); Centering The Filament (Transmitted); Aperture Diaphragm - Unitron EXAMET-4 User Manual

OPERATION
Fig. 30
Fig. 31
Fig. 32
®
UNITRON
(continued)
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EXAMET-4 SERIES MICROSCOPE

Aperture Diaphragm

- Transmitted Illumination
The aperture diaphragm decides the numerical
aperture of the illumination system. If the N.A. of
the illumination matches the N.A. of the objective,
you'll achieve better resolution and contrast and
increase the depth of field.
As the contrast is usually low, adjust the
condenser aperture diaphragm to 70-80% of the
objective N.A. being used. If necessary, remove
the eyepiece to observe through the eyepiece
tube. Adjust the aperture diaphragm adjustment
ring  to adjust proportion until you see the
image (Fig. 29).
Use of graduation: set the N.A. of the condenser
to the 80% of the N.A. of objective  (Fig. 30).
Center the Filament
- Transmitted Illumination
Turn the neutral density knob  to OUT and
observe the image of the filament through the
eyepiece by adjusting the coarse focusing knob
(adjust the brightness for comfortable
observation as shown in Fig. 10).
If the filament is not in the center of the field of
view, adjust the two knobs as shown in Fig. 32
until it is centered. The top knob  controls the
up and vertical (up/down) movement while the
side knob  controls the horizontal (left/right)
movement.
(Fig. 27-28)
(Fig. 31-32)
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