21
10. Centering the rotatable stage (Figs. 28 & 29)
(1) Place the specimen.
(2) Focus on the specimen and look for an easily recognizable detail ³
in the field. Move this detail in the center of the eyepiece cross lines.
(3) When the stage is rotated, the detail moves in circle |. Manipulate
the two stage centering knobs ƒ to coincide the imaginary center of
the circle | circumscribed by the detail with the intersection of the
eyepiece cross lines. Depending on the degree of the stage decen-
tration, this will move the specimen detail in the opposite direction,
away from the cross line center.
(4) Moving the specimen only, move a new specimen detail into the
cross line center.
} Repeat steps (3) and (4) several times until the center of the stage
rotation is in the center of the cross lines, i.e., when rotating the stage,
the specimen detail stays in the center of the cross lines.
(5) Clamp the stage with the stage rotation clamping knob.
11. This concludes centering of the optical axis for the 20X or 10X objective,
which will act as the reference objective. Now, center the other objectives
with the centerable nosepiece by engaging the objectives into the light
path one after another.
FIg. 28
Fig. 29
