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With it, some of the world’s simplest and most complex organisms were discovered. The compound microscope has been, for a long time, science and technology’s partner in seeing what cannot be seen through the naked eye. It was during the 1590s when a father-and-son tandem, Hans Lippershey and Zaccharias Hanssen, experimented with a variety of lenses and unknowingly invented the compound microscope. Today, half a millennium later, scientists and students are much more equipped to understand the world’s complexities.

A compound microscope is made up of multiple lenses, the main factor which differentiates it from a simple microscope. The word “microscope” is compound itself as it is made up of two words: “micro” and “scope” which means “small” and “view” respectively. Judging from its etymology, a compound microscope can be described as a device that allows humans to view and observe the behavior of microorganisms through multiple lenses.

It can be used for several reasons; this writer for one has used it countless times in the school laboratory for quite a number of experiments. Each experience is a marvel to recall. To use it properly, we are taught of its specific parts and its functions. Here’s a refresher:

Structural Components

  • Head – where the optical parts in the upper part of the microscope are found
  • Base – supports the microscope, also holds the illuminator
  • Arm – connects the base to the head. The safest way to carry a microscope is to lift it by the arm and base.

Optical Components

  • Eyepiece Lens - at the end of the microscope tube is the eyepiece lens, which is the actual lens you look through. It can be composed of two single lenses or two doublets. Aside from magnifying the image, it also reduces image aberrations. A standard eyepiece has magnifying power of 10x, but the typical range for all microscopes is 5x to30x.

  • Eyepiece tube – holds and connects the eyepiece lens to the objective lenses. Some binocular microscopes are equipped with a diopter adjustment ring to accommodate the variation of a person’s eyesight. Alternatively, a monocular microscope does not have one.

  • Objective lenses - the primary optical lenses of a microscope, ranging from 4x to100x magnification. They typically include three to five lenses.

  • Revolving nosepiece or Turret – holds the objectives. The turret enables the user to conveniently rotate and select from the different mounted objectives to change power.

  • Coarse and Fine Focus knobs – these are used to focus the microscope, much like what you do when adjusting a camera’s lens. Nowadays, there are microscopes that only have one knob – the coaxial focus knob. With this, viewers won't have to grope for different knobs, making it much more convenient.

  • Stage and Stage clips – the specimen to be viewed is placed on the stage, while the stage clips are used when there is no mechanical stage. A mechanical stage is particularly useful when viewing specimens that require delicate magnifications and movements. With the stage clip, viewers have to move the slide manually.

  • Aperture – a hole found in the stage through which the base light lands.

  • Illuminator – the microscope’s light source located at its base. This is used in place of a mirror in older microscope models.

  • Condenser – as the illuminator produces the light, the condenser collects and focuses it to the specimen.

  • Condenser Focus Knob - used to maneuver the condenser’s movement to control the lighting focus on the specimen.

  • Iris diaphragm – located above the condenser, the iris diaphragm controls the amount of light directed to the specimen.

These are the essential components that every microscopist should understand. There is so much to see in this complex world, and through the microscope, seeing them is possible.