How Do Telescopes Work?

Have you ever wondered how far away the stars are? Or how constellations work? Have you ever looked up into the sky and wished you could see the moon and the stars up close for yourself? You can do all of this and more with a telescope!

What is a telescope?

A telescope is a means of looking at things that are in the faraway distance. The most common way we use telescopes is to see the stars, study astronomy and view the sky up close.

A telescope is so useful for seeing objects at a great distance, and making them appear up close in pristine detail.

Most telescopes will either be a reflector telescope or a refractor telescope. The reflector telescope works with mirrors, whereas the refractor telescope will work with glass lenses.

This may have you wondering how a small bit of glass can zoom in on the stars in the sky, but don’t worry, we are here to tell you how telescopes work

How do telescopes work?

When we look at things, our sight is limited. We can only see up to a certain distance clearly, and will have to use cameras, magnifying glasses or telescopes to see details up close.

You will need much bigger eyes in order to collect enough light and brightness to be able to see a more detailed image of something at a distance. Then, you would need to magnify the image to see into it clearly.

This is essentially how a refracting telescope works. There are two major components that make a telescope magnify and display images from a distance.

The first component is an objective lens, which works to collect a lot of light from a far off object in the distance, and will bring that light and the image to focus. Then, an eyepiece lens will take that bright light and magnify it by spreading it outwards, so that we can see it clearly with our own eyes.

When both components are combined, you will have a working refracting telescope.

A reflecting telescope will on the other hand use mirrors instead of the lenses in order to collect light from a distance.

This light will then travel all the way down the telescope and towards a primary mirror, which will then work to reflect the light towards a secondary mirror, which will then reflect towards the eyepiece for us to look through.

You can also get catadioptric telescopes which will also reflect the light through a curved lens before reaching the primary mirror and going towards the eyepiece.

With every different type of telescope, it is the eyepiece rather than the lens that will determine how the image will be magnified. This is why you can purchase multiple different eyepieces such as these to change the magnification and see images much more clearly!

Generally speaking, the mirrors and lenses in your telescope can see things that are really far away. To do this, the lenses have to be quite large, to gather as much light as possible.

The bigger the lens, the more the telescope will be able to see. Then, the light will curve down the telescope body, until it reaches the smaller, magnifying lens, and then you can look through.

This works in a similar way to seeing lenses, where the thicker the lens is, the more you will be able to magnify and see. Therefore, larger lenses will be needed for refracting telescopes in order to see as much as possible.

Because light passes through the lens to show an image, the lens will have to be perfect, without any scratches or damage, in order to see clearly in the distance.

With such large, bulky lenses used in refracting telescopes, it comes as no surprise that reflecting telescopes with mirrors are much easier to use.

We can also use telescopes to capture images of far away galaxies, stars, solar systems and nebulas at a great distance! This can help us learn about the world around us, and the galaxy.

How to Use a Telescope

You will have to use a telescope in conditions and areas where there is less light pollution in order to see things like the stars. In addition, you will have to consider what you want to use your telescope for.

To view objects such as the stars or the moon, you will need a telescope that works with good contrast and a powerful resolution. This is best done with a reflector or refractor telescope.

However, if you want to view things like galaxies and nebulae, then you will need to use a telescope with a larger aperture, such as a large reflector telescope.

In addition, a telescope will need a good mount in order to work properly. Mounts like an altazimuth mount are easier to operate, by just moving up and down and side to side.

These types of mounts are perfect for beginners hoping to get into astronomy. On the other hand, you have equatorial mounts that swing across the celestial North to South and East to West axis.

Finally, you will have to position the tripod, or the legs of your telescope properly before you can begin using it. This will ensure that it stands properly and the lenses do not get damaged, or your telescope will not work accurately.


In short, telescopes work by using curved mirrors and lenses to obtain light from the sky, and distant objects, whilst concentrating the light down into an eyepiece for magnification.

We can then view far off objects and stars clearly through the telescope eyepiece. 

Gordon Watts
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