Standard Operation and Maintenance of Optical Microscopes
(1) Place the optical microscope slightly to the left on the desktop in front of you during the experiment. The base of the microscope should be about 6–7 cm away from the table edge.
(2) Turn on the light source switch and adjust the light intensity to an appropriate level.
(3) Rotate the nosepiece to align the low-power objective lens with the aperture on the stage. First, adjust the lens to approximately 1–2 cm above the stage. Then look into the eyepiece with your left eye, adjust the height of the condenser, and open the iris diaphragm fully to allow light to enter the lens barrel through the condenser, so the field of view becomes bright.
(4) Place the slide to be observed on the stage. Position the target area of the slide right at the center of the aperture, and secure the slide with the slide clips.
(5) Start observation with the low-power objective (10× objective, 10× eyepiece). Before observation, turn the coarse focusing knob to raise the stage so the objective gradually approaches the slide. Take care not to let the objective touch the slide to avoid crushing it. Next, look through the eyepiece with your left eye and keep your right eye open (develop the habit of observing with both eyes open so you can draw with your right eye while viewing). Slowly turn the coarse focusing knob to lower the stage until the magnified image of the sample on the slide comes into view.
(6) If the image in the field of view fails to meet experimental requirements (the image is off-center), slowly adjust the stage movement handle. Note that the slide moves in the opposite direction to the image seen in the field of view. If the image is blurry, turn the fine focusing knob until the image is sharp.
(7) To observe with a high-power objective, move the target area of the image to the center of the field of view before switching objectives (switching from low-power to high-power objective greatly reduces the visible area of the specimen). For normally functioning microscopes, low-power and high-power objectives are roughly parfocal. When a clear image is obtained under low power, the image should still be visible after switching to high power, though it may not be perfectly sharp. Adjust using the fine focusing knob.
