How to Use a Compound Microscope
Familiarization First, familiarize yourself with all the parts of a microscope so that you can easily move from one part to another during operation.
Moving and Placement: It is worth remembering that while a good quality microscope will last a lifetime, it is a sensitive scientific instrument that will suffer damage from sharp blows or impact. Always, therefore, carry your microscope in both hands. Grasp the arm with one hand and place the other hand under the base for support. Always place the microscope on a level and stable surface.
Slide Preparation: Microscope slides should always be prepared with a cover slip or cover glass over the specimen. This will help protect the objective lenses if they touch the slide. To hold the slide on the stage fasten it with the stage clips. You can push down on the back end of the stage clip to open it.
Focusing the Microscope:
- Start by turning the revolving nosepiece (turret) so that the lowest power objective lens is "clicked" into position. The lowest power objective is the shortest one. This objective is the easiest to focus and center the image in the field of view.
- While looking at the objective lens and the stage from the side, turn the coarse focus knob so that the stage moves upward toward the objectives. Move it as far as it will go without touching the slide.
- Now, look through the eyepiece(s) and adjust the illuminator and diaphragm until you attain the maximum, comfortable level of light.
- Slowly turn the coarse adjustment so that the stage moves down (away from the slide). Continue until the image comes into broad focus. The turn the fine adjustment knob, as necessary, for perfect focus.
- Move the microscope slide until the image is in the center of the field of view. Then readjust the illuminator or diaphragm in order to attain the clearest image.
- Once you have attained a clear image, you should be able to change to a higher power objective lens with only minimal use of the focusing adjustment. If you cannot focus on your specimen, repeat the above steps and work from objective to objective until the higher power objective lens is in place.
General Advice: You should check to see if your microscope has a rack stop. If it does not have one, then be careful not to allow the objective lens to touch the slide as you may break the slide. When using a monocular microscope, the correct technique is to look through the eyepiece with one eye and keep the other eye open. Most new users, tend to close one eye. While many microscopists do close one eye, you will help avoid eye strain by keeping both eyes open. Finally, remember! When you view a specimen through a microscope, you are viewing an image through multiple lenses. As a result, the image is upside down and back-to-front so when you move the slide to the right, the image moves to the left and vice versa!
Care & Maintenance of Your Microscope: Your compound microscope will last a lifetime if cared for properly and we recommend that you observe the following basic steps:
- When finished viewing , lower the stage, click the low power lens into position and remove the slide.
- Switch off the microscope when not using.
- Avoid touching the glass part of the lenses with your fingers. Use only special lens paper to clean the lenses.
- Dust is the number one enemy of a microscope so always keep your microscope covered when not in use. When not in use for extended periods, replace the microscope in its box.