How to calibrate a monocular microscope to ensure accurate observations?

Calibrating a monocular microscope to ensure accurate observations requires a series of steps. First, clean all optical components of the microscope, including the eyepieces, objectives, and light source, and make sure there is no dust or stains that affect the field of view. The microscope should be placed on a stable and level workbench to avoid vibration and tilt. Turn on the light source and adjust the brightness of the light so that the field of view is bright but not overexposed. Use the condenser to focus the light beam onto the sample to ensure uniform illumination. Next, place a standard sample (such as a calibration slide or a sample with a known scale) on the sample stage, use the coarse focus knob to bring the sample into rough focus, and then turn the fine focus knob to make the sample image clear.

Objective calibration starts with a low-power objective (usually 4x or 10x), observe the sample and adjust the focus to make the image clear, then gradually switch to a higher-power objective (such as 40x or 100x), using the fine focus knob to make fine adjustments each time to ensure the image is clear. Make sure the center of the sample is in the center of the field of view by adjusting the position of the sample stage, using a crosshair ruler or a scale ruler sample to observe whether the center point of the ruler is in the center of the field of view. Use a sample with a known scale (such as a glass slide with a micrometer scale) to observe the sample at different magnifications, record the scale length at each magnification, and calculate the actual magnification of the objective.

Ensure that the optical axis is aligned with the mechanical axis of the microscope. This can be achieved by adjusting the position of the condenser and light source to ensure that the light beam passes through the sample vertically to avoid image distortion caused by tilt. Use calibration software for image correction, especially in digital microscopes, to adjust the contrast, brightness, and sharpness of the image through software. Repeat the calibration process regularly, especially after long-term use or replacement of the objective lens or eyepiece, to ensure the accuracy of the calibration.