The dissection microscope consists of a base with an attached microscope arm that extends to the top of the scope where the ocular lenses sit. A stage sits on the microscope base where the specimen is placed for viewing. In some models, a mirror sits underneath this stage to reflect an internal light source. A focus knob moves the microscope arm up and down to make the specimen more clear. A separate knob is used to adjust the amount of magnification. Two adjustable ocular lenses sit at the top of the microscope arm.
Some dissection microscopes have internal light sources that illuminate the specimen from above, below or both. More commonly, dissection microscopes require the use of an external light source called an illuminator to shine light directly onto the specimen. An opaque insert with black on one side and white on the other is placed in the miscroscope stage when an illuminator is used. Internal light requires a clear glass insert to be placed in the stage to allow light to shine up through the specimen. The specimen must also be opaque for this to work.
Ocular lenses on dissection microscopes have a standard magnification of 15x. An additional 2x lens can be attached to the objective lens to double the magnification provided by the ocular lenses. Adjust the magnification by rotating the zoom dial or magnification knob on the microscope until you can visualize the object clearly. Because the dissecting microscope has limited magnification capabilities, you will not be able to see individual cells in your specimen.
Begin with the objective lens in the lowest position on the microscope arm. Adjust the width of the ocular pieces to align with your eyes. Look through the lenses and slowly run the knob to raise the objective lens until the specimen is sharp. Close your right eye and look through the left ocular lens with the left eye. Turn the adjustment dial on the ocular piece until the image is clear. Repeat for the left eye. Look through the lenses with both eyes and the specimen should be well focused.