Beginners Guide to Using a Biological Microscope for the First Time

Tips for using your microscope for the first time

It may seem complicated at first – so many knobs, so many rules. But with this quick guide, you’ll feel comfortable using your new microscope in very little time.

Microscopes differ between models, so this is one time when your instruction manual will come in handy. Use it to learn where to find all the parts of your microscope and what each one does. Then, you’re good to go.   

Locate a flat surface

Set your microscope on a flat, sturdy benchtop.

Connect to a power source

Plug the microscope’s power cord into an outlet and flip the switch on your microscope’s light source. Note: some compound microscopes don’t use mains powered lighting but have a mirror to focus natural light instead, in which case you should make sure you’re in a well-lit area.

Rotate the nosepiece

The nosepiece swings around. Always start (and end) your session by rotating the shortest lens (the 4x objective lens with the red band) over the spot where your slide will go. This low power lens gives the widest field of view and makes it easier to find the specimen when you look through the eyepiece.

Set the stage

The stage is the platform that supports the specimen slide below the objective lenses. Use the coarse focus knob (the bigger one) on the side of the microscope to set the stage as low as possible. This makes it easier to insert your slide.

Place a slide on your stage then raise it back up

Set a microscope slide (coverslip/glass facing up) in place under the stage clips, ensuring your specimen is directly over the hole that the light comes through. Then use the coarse focus knob again to raise the stage back up. Don’t worry. It won’t collide with a 4x lens no matter how high you raise it.

Raise the condenser

Use the knob that controls the condenser (if you have one) to raise it all the way up. This will focus the light and produce a better image. Lower light levels also help create a good contrast for a more detailed image. To reduce the light level, move the lever on the side of the condenser to close the diaphragm almost all the way.

Focus

It’s time to look down through the eyepiece to inspect your first specimen. Odds are, the first time you do this, you’ll the disappointed. The slide will not be in focus, and everything will be a blur. But don’t despair. There’s sure to be simple fix. If it’s too dark to see anything at all, open the diaphragm a bit. If you can see the slide but your specimen is fuzzy, slowly turn the coarse control knob until the image comes into focus. Go slow. It’s easy to miss the focus if you go too fast.

Put your target front and centre

Once your specimen is in focus, use the stage control knobs (or your fingers if your microscope lacks this function) to centre the part of the specimen you wish to magnify. This is important. It ensures the part you want to view will still be visible when you switch to higher magnifications. Searching for your lost focal point after switching lenses is much more complicated and no fun.  

Enhance the magnification

When your specimen is focused and centred, rotate the 10x objective lens (for 100x magnification) to the viewing position. It might look as though it’s too close to the slide and will hit it, but if the image is in focus there should be no danger of that. Refocus using the fine focus knob, view your specimen carefully and adjust the diaphragm again for best contrast.

Enjoy the view!