5
OPERATION (cont.)
USING THE 5-HOLE DIAPHRAGM
1. To obtain the best contrast for observing, match the hole size to  
    the objective that is being used to view the specimen. 
2. Each hole has a corresponding number from 1 to 5. 1 is the   
    smallest hole; 5 is the largest hole.
    Use the following guidelines to match the hole number to the  
    objective that you have selected: 
    40x objective: Use #5 hole
    10x objective: Use #4 or #3 hole
      4x objective: Use #2 or #1 hole
COARSE KNOB ADJUSTMENT - Model AY11240
1. The coarse adjustment knob has an adjustable heavy-light nut  
    (See Fig.1).
2. To adjust the knob loosen or tighten the nut.
    NOTE: Adjusting the nut too tight will make focusing difficult.  
    Adjusting the nut too loose will cause the tube to slide.  
Heavy-Light
Adjustment Nut
Fig. 1- Coarse Adjustment Knob
7. To clearly see the outline of the   
    specimen, rotate the coarse   
    adjustment knob and lower 
    the barrel to the space limiter.
8. Rotate the fine adjustment knob     
    until the image is in sharp focus.  
    When using other objectives, rotate  
    the fine focus adjustment until the  
    image is in focus.
6. To clearly see the outline of the   
    specimen, rotate the coarse   
    adjustment knob and lower 
    the barrel to the space limiter.
7. Rotate the fine adjustment knob     
    until the image is in sharp focus.  
    When using other objectives, rotate  
    the fine focus adjustment until the  
    image is in focus.
Model AY11240 Model AY11238
6
MODEL AY11228/AY11232
MICROSCOPE USAGE
BARSKA Model AY11228 and Model AY11232 are designed for 
biological studies such as specimen examination. They can also   
be used for examining bacteria and for general clinical and medical 
studies. Simple design and use is especially useful for school 
classroom instruction.
CONSTRUCTION
BARSKA Model AY11228 is a fixed power stereo microscope. It is 
constructed with two optical paths at the same angle. It is 
equipped with transmitted illumination and oblique illumination.  
By using this instrument, the user can observe and enlarge the 
right side stereo image. BARSKA Model AY11232 is a zoom stereo 
microscope. The object being viewed is enlarged through two 
identical sized sets of right and left eye lenses. The zoom provides 
different magnification and features an inversion system which 
allows the image to be viewed normally and right side up.
Model AY11228 Model AY11232
Diopter
Adjustment
Diopter
Adjustment
Prism
Cap
Prism
Cap
Eyepiece
Stage
Lens
Stage
Vertical 
Pole
Illumination
Controls
Rotary
Case
Illumination
Controls
Spring 
Clips
Spring 
Clips
Focus
Knob
Focus
Knob
Magnification
Adjustment
Knob
Focus
Knob
Tightening
Knob
Oblique
Illuminator
Oblique
Illuminator
Lens 
Housing
Eyepiece