Things You Must Pay Attention to When Using a Microscope
The objective lenses mainly include 4×, 10×, 40× and 100×OIL. The operation rule is to observe from low magnification to high magnification. When observing tissue sections, start with the 4× objective lens (which gives 40× magnification when combined with a 10× eyepiece). Turn the coarse adjustment knob until the image of the section appears. The light intensity can be adjusted at this stage. Then switch to the 10× objective lens (100× magnification), and turn the fine adjustment knob until the image is sharp.
A condenser is located directly below the circular opening of the stage to converge and adjust light. Below the condenser is an iris diaphragm. Its lever controls the aperture size. Together with the light source, it regulates the light intensity projected onto the back of the glass slide.
Excessively bright light leads to poor contrast and blurry specimens. In this case, reduce the iris aperture for better observation.
To use the 100× objective lens (1000× magnification), first rotate the objective turret away. Place a small drop of immersion oil on the coverslip. The immersion oil has a refractive index close to glass to prevent light scattering and deliver clearer images. Then carefully rotate the objective lens until it gently touches the coverslip. The lens sits very close to the coverslip. During focusing, take great care not to let the lens strike the coverslip and break it.
When using the oil immersion objective (1000× magnification), first raise the stage with the fine focusing knob until the coverslip lightly touches the objective lens. Then slowly lower the stage with the fine adjustment knob to search for focus. If the objective lens separates from the oil and coverslip, repeat the above step.
After finishing oil immersion observation, wipe the lens repeatedly with lens paper moistened with 95% or 99.5% alcohol, then polish thoroughly with clean lens paper.
After use, lower the stage to the lowest position, turn off the light source, and cover the microscope with the dust cover.
