Bresser National Geographic 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 first observation.
First, loosen the screw (24) and rotate the head into a convenient position.
Begin every observation with the lowest magnification.
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 magnification (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).
6. Observation
After you have set up the microscope with the proper illumination, the following prin-
ciples are important:
Begin each observation at the lowest magnification, so that the centre and position
of the object to be viewed is in focus. The higher the magnification, the more light is
required for good picture quality.
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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 magnification. 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 magnification is raised to 2X.
For even higher magnification, you can put the 16X eyepiece (2) into the objective
revolver (6) and rotate the objective revolver to a higher magnification (10X or 40X).
TIP:
i
Depending on the preparation, higher magnifications do not
always lead to better pictures.
When changing the magnification 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.
NOTE:
Please be very careful when doing this. If you move the mechanical
plate upward too fast, the objective lens and the slide can touch and
become damaged.
7. Condition and prepare viewed objects
7.1. Condition
With the Barlow lens nearly fully extended, your microscope's magnification can be
doubled. Both transparent and non-transparent specimens can be examined with this
microscope, which features both direct and transmitted light. If opaque specimens are
being examined, such as small animals, plant parts, tissues, stones and the like, the
light is reflected from the specimen, through the lens and eyepiece, where it is magni-
fied, to the eye (reflected light principle, switch position I). If opaque specimens are