Aperture Diaphragm; Use The Oil Objective (100X) - BestScope BS-2026 Series Instruction Manual

Fig. 11
Fig. 12
BestScope International Limited
3-5

Aperture Diaphragm

1. The aperture diaphragm decides the numerical
aperture of the illumination system. Only when
the N.A. of illumination system is matching with
the N.A. of the objective, it can obtain better
resolution and contrast, and also increase the
depth of field.
2. For the microscope with disc diaphragm, turn
the diaphragm to select a aperture to get the
background brightness suitable (see Fig. 11).
3-6

Use the Oil Objective (100X)

1. Use the 4X objective to focus the specimen.
2.Place a drop of oil① on the specimen observed
(see Fig. 12).
3. Rotate the nosepiece counterclockwise and
rotate the oil objective (100X) into the light path.
Then use the fine focusing knob to focus.
★ Make sure there is no air bubble in the oil for
fear affect the image.
A. Move the eyepiece to examine the air bubble.
Open the aperture
diaphragm fully and observe the edge of the
objective field (It seems round and bright).
B. Rotate nosepiece slightly and swing the oil
objective to remove the air bubble.
4. After using, wipe the front lens with a tissue
moistened with a small amount of 3:7 mixture of
alcohol and ether or with dimethylbenzene. Wipe
off the oil on the specimen.
★ Don't put another objective to the light path
before the oil is wiped to avoid wetting the dry
objective.
★ Too much dimethylbenzene would dissolve
the lens's stickiness.
8
BS-2026 Series
diaphragm and field