Operating Method of the Low‑power Objective for Optical Microscope
① Taking out and placing the microscope: The microscope is normally stored in a cabinet or case. When in use, take it out from the cabinet. Hold the microscope arm firmly with your right hand and support the base with your left hand. Place the microscope on the bench in front of your left shoulder. The rear end of the base should be 1–2 inches away from the table edge for comfortable seated operation.
② Aligning the light: Use your thumb and middle finger to rotate the nosepiece (never hold and move the objective directly) to align the low‑power objective with the aperture of the stage. A clicking sound indicates that the optical axis of the objective is centered with the barrel. Open the diaphragm, raise the condenser, and turn the mirror toward the light source. Observe through the eyepiece with your left eye while keeping your right eye open. Adjust the angle of the mirror until the field of view is evenly and brightly illuminated.
③ Placing the slide specimen: Put the slide specimen on the stage with the coverslip side facing upward (do not place it upside down). Secure it with the spring clips of the mechanical stage. Turn the stage control screw to move the target area directly above the aperture.
④ Focus adjustment: Turn the coarse adjustment knob counterclockwise with your left hand to slowly raise the stage until the objective is about 5 mm above the specimen slide. Do NOT look through the eyepiece while raising the stage; watch from the side to avoid collision and damage to the lens or slide. Then keep both eyes open. Look through the eyepiece with your left eye and slowly turn the coarse adjustment knob clockwise to lower the stage until a clear image appears in the field of view.
If the image is off‑center, adjust the mechanical stage to center it (note: the slide moves in the opposite direction to the apparent image movement in the view). If the brightness is unsatisfactory, adjust the height of the condenser or the aperture of the diaphragm. If the stage has moved beyond the working distance (>5.40 mm) without an image appearing, the focusing attempt has failed. Restart the procedure and avoid hastily raising the stage blindly.
