Optika Italy B-1000 Serie Manuel D'instructions page 13

Centering the
condenser
Insert the swing-out lens of
the condenser ① and fully clo-
se the field diaphragm ②. Ro-
tate the condenser adjustment
knob ③ until you see a sharp
image of the closed field
diaphragm (a bright spot of
light). Act on the condenser
centering screws ④until you
move the bright spot in the
center of the image field. Then
re-open the field diaphragm
②. (Fig.25)
Adjust the aperture of the iris
diaphragm under the conden-
ser to set the numerical aper-
ture of the illuminator, thus
controlling image contrast and
resolution. It is suggested to
set the aperture diaphragm
between 70% and 80% of
objective's N.A. (Fig.26)
Centering the stage
With the Bertrand lens out,
focus on your slide. In this
procedure we'll center the
optical axis of each objective
with the rotation axis of the
stage. Insert the 10x objecti-
ve, rotating the nosepiece.
Look at your sample while
continuously rotating the
stage clockwise and then
counter-clockwise by a little
angle (e.g. 30° or 45°). During
these oscillations you should
spot a point on the sample
that doesn't rotate on a cir-
cumference but only revolving
about itself (it is the center of
the rotations). (Fig.27)
③
①
A= FIXED POINT
(Center of rotation)
B= ROTATING POINT
Page 13
CENTERING THE CONDENSER
APERTURE IRIS
DIAPHRAGM IMAGE
OBJECTIVE PUPIL
Center of rotation on the optical axis.
④
②
Fig.25
70-80%
30-20%
Fig.26
Fig.27