Microscopes are mechanical devices used for viewing objects and materials so minute in size that they are undetectable by the naked eye. The process conducted with such an instrument, called Microscopy, uses the combined schools of optical science and light reflection, controlled and manipulated through lenses, to study small objects at close range.

The basic microscope consists of several complex and interrelated parts: a cylinder that provides a necessary space of air between the ocular lens (eye piece) situated at the top and the objective lens fixed at the bottom, hovering close to a stage containing an optical assembly on a rotating arm and a centered hole through which a light shines from a solid U-shaped stand beneath. Magnifying values for the ocular range through X5, X10, to X20, while the values for the objective lens has a broader span: X5, X10, X20, X40, X80, and X100. These values provide the observer with a spectrum of possible distance orientations and degrees of sharpness as are necessary for viewing and analysis.

Several different kinds of microscopes exist, each having particular features:

Optical Microscope: The first ever created. The optical microscope has one or two lenses that work to enlarge and enhance images placed between the lower-most lens and the light source.

Simple Optical Microscope—uses one lens, the convex lens, in the magnifying process. This kind of microscope was used by Anton Van Leeuwenhoek during the late-sixteen and early-seventeenth centuries, around the time that the microscope was invented.

Compound Optical Microscope—has two lenses, one for the eyepiece to serve the ocular perspective and one of short focal length for objective perspective. Multiple lenses work to minimize both chromatic and spherical aberrations so that the view is unobstructed and uncorrupted.

Stereo Microscope: This is also known as the Dissecting Microscope, and uses two separate optical shafts (for both eyes) to create a three-dimensional image of the object through two slightly different viewpoints. This kind of microscope conducts microsurgery, dissection, watch-making, small circuit board manufacturing, etc.

Inverted Microscope: This kind of microscope views objects from an inverted position than that of regular microscopes. The inverted microscope specializes in the study of cell cultures in liquid.

Petrographic Microscope: This kind of microscope features a polarizing filter, a rotating stage, and gypsum plate. Petrographic Microscopes specialize in the study of inorganic substances whose properties tend to alter through shifting perspective.

Pocket Microscope: This kind of microscope consists of a single shaft with an eye piece at one end and an adjustable objective lens at the other. This old-style microscope has a case for easy carry.

Electron Microscopes: This kind of microscope employs electron waves running parallel to a magnetic field providing higher resolution. Two Electron Microscopes are the Scanning Electron Microscope and the Transmission Electron Microscope.

Scanning Probe Microscope: This kind of microscope measures interaction between a physical probe and a sample to form a micrograph. Only surface data can be collected and analyzed from the sample. Types of Scanning Probe Microscopes include the Atomic Force Microscope, the Scanning Tunneling Microscope, the Electric Force Microscope, and the Magnetic Force Microscope.

Science wouldn’t be what it is today without the microscope, as this device is the primary instrument by which the world and all of its elements are measured and assessed. It is with the microscope that we take a look inside of ourselves so we can learn and understand who we are and how we work.

by Alexander Sutton

A reflecting telescope is one of two kinds of optical telescopes, refracting and reflecting. A reflecting telescope uses a single or combination of curved mirrors which reflect light to form an image. The reflecting telescope was invented in the 17th century as an alternative to the refracting telescope. The reflecting telescope was made to correct the server chromatic aberration that was part of working with a refracting telescope. Reflecting telescopes also create other aberrations, but they allow for a very large diameter which is helpful with research telescopes. The reflecting telescope comes in many designs which improve image quality. Reflecting telescopes are often referred to as “catoptric” telescopes.

There are many technical considerations to be aware of when using a reflecting telescope. Various aberrations are caused by the reflecting telescope, such as that the inner and outer zones of the telescope may not share the same focus. Spherical aberration can be eliminated with non-spherical mirrors.

Other aberrations are also common with reflecting telescopes. A coma may appear which is when a variation of telescope magnification may cause radial smudging which worsens at the edge of the visual field. Astigmatism may also occur around the focus of the aperture. Distortion of the field of view does not affect objects, but may harm sharpness. The best image plane is in general curved. This may not correspond to the detectors shape and may later cause focus errors. There are other reflector designs referred to as catadioptrics that correct some aberrations.

The majority of research-grade telescopes are reflectors. This is because, unlike a lens, the mirror does not need to be free of imperfections; it merely needs to be polished. Also, light of different wavelengths travels through a medium other than a vacuum at different speeds. The reflectors also work in a wider spectrum of light because certain wavelengths are absorbed when passing through lenses in comparison to reflecting off of them.