How a Telescope Works

Have you ever wondered how different telescopes work? Let’s take a closer look at each of them to see how they work.
Liam Black Jul 1, 2019
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Looking up through a telescope at the stars can fill us with a sense of wonder. Often, these sights inspire questions about how the stars were formed and the mechanics of the universe. But, have you ever wondered how a telescope works?
There are many telescopes available, ranging from ones to suit professional astronomers to the telescopes for beginners. However, they can be divided into two main types; refracting and reflecting telescopes.

Principles Behind The Telescope

There are a few basic principles that all telescopes share. First, they need to find a way of magnifying the light. This is done by using mirrors or lenses.

Once the light has been magnified, an eyepiece is then required. This allows to focus on the distant objects. With the eyepiece, one can adjust the telescope to make the image clearer.
Generally, the further away from the object, the more light needs to be gathered. For this, you will need to use larger mirrors or lenses. Though the general principles are the same, there are two main types of telescopes.

Let’s start by examining how the refracting telescope works.

Refracting Telescope

This telescope uses lenses to magnify light. At the front, a large lens gathers and magnifies the light, which is focused on another lens at the base of the telescope.
It also stops air distortions from affecting image clarity. Often the thickness of the lens separates telescopes for beginners from the more serious astronomical equipment.  One major benefit of this telescope is, that the tube is sealed at both ends to prevent entrance of dirt.
The thicker the lens, the more powerful is the telescope. However, this can restrict the extent to which the image can be magnified.
For example, if the lens gets too thick, the light will no longer be able to penetrate. Also, thicker lenses can often make the telescope heavier. Finally, these telescopes rely on high-quality lenses.

Let’s now examine the reflecting telescope, which is also most widely used.

Reflecting Telescope

Reflecting telescope uses mirrors to magnify the image. Light enters through the top of the telescope, where it becomes more concentrated as it gets bounced from a series of mirrors. One of these mirrors will need to flip the image, so the observer can see the image right way up.
Finally, the light is reflected in the lens, which the astronomer looks through. You can use this lens to adjust the image to make it clearer. This model has a few advantages over refracting telescopes. First, mirrors are easier to position than lenses. In addition, they are usually easier to maintain.
There are many types of telescopes available, though they are based on the two systems as discussed.

However, most professional telescopes use reflecting technology. Hence, it is the most popular type of telescope used. There are a few reasons for this.
First, it’s easy to produce high-quality mirrors than it is to produce high-quality lenses. In addition, mirrors tend to be lighter. This makes it easier for organizations like NASA to assemble and send telescopes, like the Hubble Space Telescope, into the space.
Finally, reflecting telescopes tend to be the cheapest type of telescope to make. However, when choosing a telescope for beginners, both models will work well. Hopefully, you now have a greater understanding of the science behind the telescope.