10
a)
Centering
–The condenser must be
centered in the light path to ensure
proper light control. One simple
method for centering follows:
i) Rotate the objective nosepiece until
the 5X objective is in the light path.
ii) While looking into the microscope,
close the field diaphragm to the
smallest setting using the knurled ring
at the top of the light exit window
assembly.
iii) Closing the iris in this manner will
reduce the field so that a small white
circle is visible within a black field, see
Figure 8A. This white circle is the light
that is passing through the iris and it should be centered in the black field
as in Figure 8b. If it is not centered, move it to the center using the
centering screws.
iv) By opening the iris until the white circle almost fills the entire field,
see Figure 8C.
b)
Vertical Focusing–
The condenser can be raised and lowered with the
sub-stage adjustment knob in order to focus the light for optical
illumination.
c)
Aperture Adjustment–
The contrast can be adjusted with the iris
diaphragm adjustment lever on the condenser assembly. Aperture
adjustments are made to induce contrast into a specimen, not to adjust
light intensity.
A
B
C
Figure 8
Substage
Adjustment Knob
Figure 7
