Align Optical Components
Koehler Illumination
PROCEDURE: Transmitted Light
1. Focus on specimen with the objective
to be used for data collection.
2. Close down the luminous field dia-
phragm (1) while viewing.
3. Raise or Lower condenser vertical
control slightly (2) until luminous field
diaphragm image is in focus.
4. Center luminous field diaphragm im-
age using condenser centering screws
(3).
5. Open luminous field diaphragm (1) to
edge of field.
6. Adjust contrast using condenser
aperture diaphragm slider (4). In most
cases adjust aperture diaphragm slider
to mark matching the NA of the objec-
tive selected. For 20x, 40x, 63x and 100x
use step 7.
7. Remove eyepiece (5) and check to see
that 75%-80% of visible aperture is filled
with light (more light=better resolution
but less contrast).
Note: this should be done every time an
objective is changed.
Benefits of Aligning Optics:
• Evenly illuminated image.
• Brilliant image without reflection or
glare.
• Minimum heating of specimen.
