You may be doing your homework on different types of optics, or you may be curious about how microscopes stack up to telescopes.
They have similar features and seemingly provide the same result – a magnified view of an object.
What is their purpose and why are there distinct markets for both?
Whether you’re in the market for a microscope or just curious, here are some facts about it, how they are similar to telescopes, and how they are very different.
It’s a seemingly natural thing to automatically think of space when one hears the word telescope. It makes sense. You use a telescope to look at distant object like the moon, planets, galaxies, stars, and more. Why is that?
It was Galileo Galilei’s intention to invent such a device to observe the universe in the early 1600s. Yes, the refractor which is a telescope type is that old. There are also other types of telescopes such as:
- Dobsonian (reflector)
And more. These are just some of the more popular types known to amateur astronomers. However, there are also radio, infrared, gamma-ray, x-ray, and more types of telescopes that scientists use.
How do Telescopes Work?
Each type of telescope design has a unique optical path. Some use glass lenses, some use mirrors, and others use a combination of both. The concept, however, remains the same across the board. A primary mirror or lens is used to “gather” or “collect” light to see astronomical objects.
Additional optical parts and accessories are used to allow the user to see a formed image with magnification.
When you think of microscopes, an image of a scientist or doctor in a white lab coat comes to mind, and it can very well be an accurate image. Unlike telescopes that are used to observe distant objects, a microscope is used to observe objects that are right in front of you. Typically, this object would be placed onto a base or plate of some sort to be examined through the microscope.
Many types of professionals use microscopes for examining multiple types of objects or procedures. A small handful of examples include:
- Human, animal, and plant cells
- Bacteria and parasites
- Drug structures
- Circuit boards
While many amateurs and hobbyists own microscopes for personal use or for school projects and inside the science classroom at schools, there are many different types of professionals who use them for very different purposes. These professionals include:
- Forensic doctors
- Science teachers
There are several types of microscopes in the market. The most common are:
- Compound light
- Handheld or Pocket
How do Microscopes Work?
Each type of microscope works a little differently due to its design, just like how different types of telescopes work differently to achieve the same outcome. Some provide 3D observation, others allow observation on an electronic device like a laptop, and the compound is used in the traditional way we can would imagine – looking through the eyepiece.
Accessories and modifications can be made to microscopes to enhance the observation experience and optical quality.
Telescope VS Microscopes
This is not a competition between telescopes and microscopes as they have very different purposes. Instead, this is a comparative review of shared features so that you can clearly see the differences between them.
Telescopes are widely available in the amateur market and can be found in many homes for recreational and serious amateur use depending on the dedication to the hobby. Some telescope owners have built or bought their own domes for storing and using their large telescopes. Even larger telescopes are used in observatories for use by the public. Many astronomy clubs will travel together to a location and setup a stargazing party in the field. Scientists also use telescopes in observatories while huge telescopes are launched into space.
There are many types of microscopes that lend itself to field work and others that stay put in a laboratory or other such workplace. Because they are used for various purposes and by different types of professionals, it can be found in multiple workplace situations.
Both telescopes, namely the refracting telescope, and microscopes use objective lenses. They both have eyepieces and the primary goal is to provide a closer look at an object with magnification. How they go about it is very different.
The job of the objective lens in a telescope is to be as large as necessary to allow as much light into the tube as possible to achieve its goal. Apertures can range between 2” to 16” and larger. Some amateur telescopes can be as large as 42”, however, they are unwieldy and very expensive.
Microscopes don’t need to “collect” light the same way a telescope does, so the objective lenses don’t have to be as large. They are not looking for an object that is at a considerable distance away. In fact, the object is placed very near to the objective lens, so a close-focus distance is more important than being able to focus to infinity.
Aperture will vary between microscopes, and because objective lenses are one of the most complex components of the microscope, there are several factors involved. Other than just the numerical aperture, you must consider objective lens type for the purpose at hand, objective standard, refractive or reflective objectives, and what level of magnification you wish to acquire.
In this case, we are specifically speaking of the objectives and eyepieces. A telescope has a primary mirror or objective lens that is one of the primary considerations you must consider when buying a telescope because you can’t “change” it out. Included eyepieces are less of a concern because eyepieces are interchangeable. You can upgrade, replace, and use different size eyepieces to achieve different levels of magnification and field of view.
Microscopes on the other hand work a little differently. They usually have a fixed eyepiece with interchangeable objectives. Some microscopes allow “stacking” of different size objectives to achieve an intended purpose.
Objective focal lengths and the eyepiece are inseparable when determining magnification for a microscope. Objective numerical apertures range between 0.10 to 1.25 which is the same as focal lengths of 40 mm to 2 mm.
Objectives may come with a colored band indicating the magnification it offers. It may also indicate it with a numeric value followed by an “X.” Combine this with the magnification value of an eyepiece, and you have your total magnification for observing a specimen.
For example, a 10x eyepiece combined with a 4x objective will provide 40x magnification. Microscopes typically provide magnification of around 4x to 100x. Stereo microscopes can make use of 200x and compounds can have stacked objectives to provide up to a max of 1000x.
With telescopes, the magnification is calculated by taking the focal length of the telescope and dividing it by the focal length of the eyepiece. For example, 1200 mm / 25 mm = 48x. Most entry-level telescopes will function best with low power usually under 60x. The larger the aperture and longer the focal length, the higher magnification – that is, useful magnification.
Just as important as it is to have the right specs, a larger aperture can provide the optical quality needed to resolve details on the object at such high power. Telescopes typically provide a useful magnification range of 10x to 150x. Higher-quality scopes can provide higher, useful powers along with additional accessories such as a Barlow lens.
The focal length is the distance from the center of the lens to the point where light rays meet to form a focal point. Parallel light rays fall onto a focal plane. These focal points are found behind the objective lens and this distance is measured in millimeters. These focal points are important because it’s where an image is formed to be seen through the eyepiece.
From what we’re gathering so far, it’s fairly easy to come to the assumption that telescopes have long focal lengths and microscopes have shorter focal lengths. That assumption is correct.
Telescopes need longer focal lengths to support longer optical paths to collect more light and focus on distant objects with larger image scales at high magnification.
Microscopes can make the best use of shorter focal lengths because the object is very close to the highly spherical objective lens. They can provide very enlarged image scales for the eyepiece to deliver a clear, usable image to the human eye.
Use of Light
Telescopes do not have a light source of their own, therefore the aperture is an essential consideration. The larger it is, the better it is at collecting natural light to see a dimmer object that is further away.
Because a microscope’s objective is very small and the specimen to be observed is very close, it’s difficult for it to gather light on its own in the same sense of how a telescope gathers light over distance.
Instead, many microscopes incorporate an artificial light source that is focused on the specimen by a condenser lens system. This light also travels through the microscope so that you can see the illuminated specimen through the eyepiece.
Shedding a Little Light on Telescopes VS Microscopes
Knowing these are two, different optical instruments, you can make an informed decision on what it is you need. By now, it should be more than obvious what type is exactly right for you.
If you’re studying for an upcoming exam where you must observe photosynthesis in action or you want to view microscopic cells that are invisible to the human eye, a microscope it is.
If your sights are set on the heavens to explore the wonders of deep space, a good telescope it is.
Learning the differences between a telescope and microscope should be a humbling experience. It really shows how science has come a long way to the days of yester-year when curved lenses were used in Greece in the 5th century BC or the crude but functional refractor of 1608.
To have such high-performing tools in the palm of our hands for affordable prices is a gift handed down to us from many ingenious inventors of the past. Thanks to modern science and engineering, we can improve upon them to further both scientific research and our personal interests today.