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B. Interpupillary adjustment of head. (Only for models B1-220 and B1-223) 

1. Look through the eyepiece and adjust the distance between the eyepiece tubes (14) by grasping the head, by its four gripped corners (13), and moving it horizontally. 

2. When a full field of view is observed through both lenses, and images blend into one, the interpupillary distance is correct for the user’s eyes. Take note of the index reading marked in the interpupillary scale (2) for the following step. 

3. Adjust the diopter scales (14) situated on both eyepiece tubes until the reading of both scales coincides with the value of the interpupillary distance scale. This step is necessary to maintain the parfocality of the objectives. 

C. Focusing the microscope. 

4. Readjust the diopter scales for variation in interpupillary distance. 

1. Turn the revolving nosepiece (3) and place the 4X objective (4) in the optical path ensuring that it is properly clicked into place. 

2. Turn the coarse focus knob (19) until the stage (8) is in its lowest position. 

3. Place a microscopic sample on the stage, make sure the cover slip faces upwards. 

• Swing the moveable finger (5) on the mechanism (6), place specimen against fixed side of slide holder (7) and gently release the moveable finger until the specimen is supported in place. 

4. Make sure that the specimen is in the optical path by adjusting the stage using the knobs controlling the X/Y movements (21). 

5. Looking through the eyepiece, turn the coarse focus knob until the preparation appears in focus. 

6. Readjust the focus with the fine focus knob (20) until the image appears sharply defined. 

D. Adjust diopter for differences in eyesight. (Only for models B1-220 and B1-223) 

1. With your right eye, look into the right eyepiece tube (1) and adjust the sharpness of the image using the fine focus knob (20). 

2. With your left eye, looking through the left eyepiece, adjust the focus by rotating the diopter corrector (14) on the left hand eyepiece tube until the image is sharp. Do not use the fine focus knob. 

E. Adjusting the aperture of the diaphragm. 

The aperture of the diaphragm (9) should not be used to control the brightness of the light. Diaphragms are designed to obtain high resolution of the sample, and provide contrast in the image. Smaller apertures will deliver higher contrast to image. However, closing the aperture too much will reduce resolution. Experimentation is the best method of determining the correct aperture of the diaphragm. Suggested apertures for each objective are as follows: 

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