Bresser NATIONAL GEOGRAPHIC 40X-1280X Mode D'emploi page 12

4. Interchangeable illumination lenses
Your microscope comes with two illumination lenses (14 and 15). Depending on
the object to be viewed, the proper lens should be attached to the LED illumination
(9). The ground glass, or matted lens (14) is already mounted on the lighting unit.
To change the lenses, simply screw one off and the other on by turning the upper
part of the transmitted light unit (9) (see also page 11).
An overview of lens purposes:
The matted lens (14) should be used for
• viewing extremely small items with the eyepieces (1 and 2) and the Barlow lens
(3).
The condenser lens (15) should be used for
• viewing standard items with the eyepieces (1 and 2) and the Barlow lens (3).
5. Microscope setup
The microscope head (5) will now be prepared for your fi rst observation.
First, loosen the screw (16) and rotate the head into a convenient position.
Begin every observation with the lowest magnifi cation.
Place the microscope's table (7) with the focus knob (8) into the lowest position and
rotate the objective revolver (6) until it locks on the lowest magnifi cation (4X).
NOTE:
Make sure to place the microscope's table (7) in its lowest
position before changing the objective in order to prevent
damage to the microscope.
Insert the 10X eyepiece (No. 1, 1) in the Barlow lens (No. 1, 3).
Take care that the Barlow lens is inserted completely into the monocular head (No.
1, 4).
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6. Observation
After you have set up the microscope with the proper illumination, the following
principles are important:
Begin each observation at the lowest magnifi cation, so that the centre and position
of the object to be viewed is in focus. The higher the magnifi cation, the more light
is required for good picture quality.
Place a permanent slide culture directly under the microscope lens on the plate (7).
The specimen to be examined must be directly over the lighting.
Look through the eyepiece (1 and 2) and carefully turn the focus wheel (8) until you
can see a sharp picture.
Now you can progress to a higher magnifi cation. Slowly pull the Barlow lens (No.
2, 3) out of the monocular barrel (No. 2, 4). When the Barlow lens is nearly entirely
pulled out, the magnifi cation is raised to 2X.
For even higher magnifi cation, you can put the 16X eyepiece (2) into the objec-
tive revolver (6) and rotate the objective revolver to a higher magnifi cation (10X or
40X).
When changing the magnifi cation of your microscope by changing or adjusting the
eyepiece, objective lens or Barlow lens, you must readjust the focus wheel (8) to
sharpen the image.
TIP:
i
Depending on the preparation, higher magnifi cations do not
always lead to better pictures.
NOTE:
Please be very careful when doing this. If you move the mechani-
cal plate upward too fast, the objective lens and the slide can
touch and become damaged.