SOP and Maintenance Guidelines for Optical Microscopes
① Place the microscope slightly to one side on the desktop before the seat during the experiment. The base of the microscope should be about 6–7 cm away from the edge of the table.
② Turn on the light source switch and adjust the light intensity to an appropriate level.
③ Rotate the objective turret to align the low‑power objective with the aperture of the stage. First adjust the objective to approximately 1–2 cm above the stage. Then look through the eyepiece with your left eye, adjust the height of the condenser, and open the iris diaphragm to its maximum. Light will enter the barrel through the condenser, producing a bright field of view.
④ Place the slide specimen on the stage, position the target area of the specimen right above the aperture, and secure the slide with the specimen holder.
⑤ Start observation with the low‑power objective (10× objective, 10× eyepiece). Before observation, turn the coarse focusing knob to raise the stage and bring the objective close to the slide. Take care not to let the objective touch the slide to avoid damaging the lens or crushing the specimen. Then look through the eyepiece with your left eye and keep your right eye open (develop the habit of binocular observation so that you can draw with your right eye while observing). Slowly lower the stage by turning the coarse focusing knob until the magnified image of the specimen comes into view.
⑥ If the image is not positioned as required (offset from the field of view), slowly adjust the stage movement handle. Note that the moving direction of the slide is opposite to the moving direction of the image seen in the field of view. If the image is blurry, turn the fine focusing knob until the image becomes sharp.
⑦ For further observation with a high‑power objective, move the target area of the image to the center of the field of view before switching objectives (the field of view becomes much smaller after switching to high power). For normally calibrated microscopes, low‑power and high‑power objectives are nearly parfocal. When a clear image is obtained under low power, an image should still be visible after switching to high power, though it may not be perfectly sharp. Use the fine focusing knob for adjustment.
⑧ After switching to the high‑power objective and obtaining a visible image, adjust the iris diaphragm or condenser height as needed to achieve suitable illumination (the field usually darkens after switching from low to high power, so light intensity needs readjustment).
⑨ After finishing observation, shift the objective away from the aperture, open the iris diaphragm fully, lower the stage slowly, and inspect all components for damage. Pay special attention to checking whether the objective is contaminated with water or oil. If contaminated, clean it with lens paper. The microscope can be packed away once inspection and cleaning are completed.
