Home >> Science & Nature >> Science

How to Use the Coarse Adjustment Knob

Whether you want to peek at skin cells or get a close up view of an insect's body, you must follow certain procedures to effectively use a binocular-style microscope. You can't just pop a slide in it and peer through the lens if you want a clear image. There are two knobs to adjust the focus: the coarse adjustment knob and the fine adjustment knob. The first step to get the sharpest view through a microscope is to use the coarse adjustment knob. This knob allows you first to focus on the slide, so you can then use the fine adjustment knob to gain the sharpest image.

Things You'll Need

Microscope

Instructions

- 1
  Turn the coarse adjustment knob a little bit both ways to determine which directions bring the slide closer versus farther away from the nosepiece. Do not look through the ocular lenses yet. Watch the slide from the side of the microscope. Turn the coarse adjustment knob slowly until it almost touches the nosepiece. Be careful not to allow the slide to touch the nosepiece because it could break the slide.
- 2
  Look through the ocular lenses and slowly turn the coarse adjustment knob in the direction that brings the slide farther away from the nosepiece. Stop turning the coarse adjustment knob when the slide is in clear view.
- 3
  Turn the fine adjustment knob to reach the sharpest image of what is on the slide. You may need to slightly turn the coarse adjustment knob for fine-tuning, although it is usually unnecessary.

Science