68
Transmitted light lamphousing 106
*
Remove any diffusing screen(s) and filters from
the light path (Fig. 9 and 10).
Method I:
UCR
and
UCPR
condenser (Fig. 14a):
turn in a
10x
objective.
UCE
condenser (Fig. 14b):
turn in a
5x
objective.
Raise the condenser to its highest position
(48.12).
Focus the specimen and find an empty area.
Switch the condenser disc (48.14) to position H
(= brightfield).
Dis
engage the condenser top (48.15).
Open the aperture diaphragm (48.21).
Slightly narrow the field diaphragm (48.22).
Remove one eyepiece from the tube and look
into the open tube from a distance of a few cm.
Adjust the collector (48.19), looking through the
eyepieces at the same time, until the reflected
image of the lamp filament (Fig. 47a) can be seen.
Adjust the centering screw (48.18) for the hori-
zontal lamp adjustment with a screwdriver until
the blurred, bright, vertical line (= overlapping of
image and reflection of the filament) is in the
centre of the bright circle. Reduce lamp
brightness to do this if necessary.
Adjust the centering screw (48.17) until the
image of the filament is in the centre of the field
in vertical direction as well (Fig. 47). Put the
eyepiece back on the tube and put the filters
and diffusing screens back in the light path.
Alternatively, you can focus on the image of the
filament with a Bertrand lens or auxiliary
telescope (Figs. 50 and 51, condenser top swung
in, use objective 40 x to 63 x, swing out polarizer
48.25).
Method II:
Lay the adjustment device* (Fig. 47a) on the
window in the microscope base and adjust the
image of the filament visible inside, as with
method I, using the collector and centering
screws (48.19, 48.17, 48.18).
Fig. 47a
Lamphousing 106
Reflection of the lamp filament, greatly schematized: in reality
the reflection is extremely low in contrast. In incident light the
bright overlap area is wider and less defined.
Fig. 47b
Adjustment device for transmitted light source
