Revised 03/25/2020
10
5.)
Condenser Astigmatism
Note: Condenser lens astigmatism should be corrected when the beam does not
expand in a symmetrical, circular fashion when the “Intensity” knob is adjusted.
Astigmatism must be corrected separately for each spot size that is used.
a.)
Converge
the beam to crossover (LC “Intensity”) and
center
it with the
beam
shift
(LC trackball).
b.)
Select
“
Condenser
”
on
the
“
Stigmator
” control panel (the panel
can also be brought up by pressing
the “Stigmator” (LC) button).
c.)
Spread
the beam and use the
MF
knobs
to make the beam as
circular
as possible.
d.)
Select “None” on the “Stigmator”
panel (or press the LC “Stigmator”
button) to end stigmator control.
6.)
Specimen Height Adjustment
Note:
all alignments beyond this point depend on the objective focus. To ensure
proper alignment, both the specimen and objective lens focus must lie on the
eucentric plane
of the microscope. This step will position the specimen.
a.) Find a point of interest on the specimen using the stage trackball (RC).
b.)
Activate the “
Alpha wobbler
” (LC button L2, by default). The stage will begin
rocking through a tilt range of +/− 15°.
c.)
Minimize
the
specimen movement
by adjusting the “
Z-axis
” control buttons
(RC). These buttons are pressure sensitive; pressing harder = faster change.
d.)
Deactivate
t
he “
Alpha wobbler
”.
Alternatively:
the eucentric height can also be set by using the “
Eucentric
focus
” button (RC) to focus the objective lens on the eucentric plane. The
specimen can then be brought into focus using the “
Z-axis
” buttons. When it is in
focus, it is located at the eucentric plane of the microscope.
