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How Does A Telescope Work?

Do you want to know how does a telescope work? Telescopes work in a way that you can see the distant abject easily. It works to collect the light and then magnify the light from the distant objects. There is extremely different to see the objects from the sky and earth.

The sky is a huge difference from the earth. It is difficult for you to see the sky and its objects from distance. But telescope helps you see them. It helps you to focus on the distant objects which are so far from us and are fainted. When you see them through the telescope it can be clear to see them.

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The telescope works via the collection of light. The more light it collects the more clearly you can see the objects. More light makes them faint and it helps the telescope to focus on the objects which help you to see clearly. The light collecting ability of a telescope is determined by its diameter, also known as its aperture.
If you study the telescope, they initially work with the curved, clear glass object which is known as the lens. But nowadays, most of the telescopes work with these curved mirrors to see clearly and to focus on the objects, especially at night.

The shape of the lens matter in a fact. These shapes help the telescope to focus on the object. Moreover, it helps to concentrate on the object. This is the light that helps to focus and see the object.

How do optical telescopes work?

First of all, you need to know about the optical telescope. There we will consider a few basic telescopes. If you are interested to buy a new telescope you must need to learn some basic knowledge about it. You also need to know about its basic design. There is two basic design for it:

  • Reflecting telescopes, which are also called reflectors.
  • Refractors telescopes, which are also called refractors.

A refractor kind of telescope uses the lenses which are present in the tube because it refracts the light. It is a kind of telescope that was used by astronomers at the previous ancient time, like Galileo. Reflectors use the mirrors to reflect light instead of lenses.

If you talk about modern observation, you will the reflectors telescopes are uses nowadays. Refractor telescopes cannot be used practically because they have large, heavy lenses. Moreover, their tubes need to be long enough to see the objects.

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What are the parts of a telescope?

There is a long tube in the refractors which is used to place lenses. This tube contains lenses. There is a type of lens known as an objective lens. This is placed at the front of the tube and this is used to call the front lens.
Now, if you talk about the modern refractor telescope it has another tube along with the first one.

This tube contains an eyepiece and an ocular lens. The eyepiece is used to see the object. It has the same meaning as its name.

This is the part through which you see the object from your eye. If you see the refractor telescope it contains multiple lenses. You can adjust the lenses to focus on the object to see clearly.

What is the small-angle approximation?

This is a common angle that is mostly used in optics. If you see about the angles, there is a small angle the tangent is an angle that is in the radian. When the angle in the radian is divided by 57.29 then this is the angle in the radian, and it is in the degrees.

This can be a good approximation and can be up to 10 degrees. This can be more in degrees. At 10 degrees, the tangent is 0.1762, and the angle in radians is 0.1745 radians.

The eye:

The eye, the most important part of the telescope. This has a simple lens which it uses to form an object on the retina. This occurs with a small approximation. The eye can focus easily on the objects that are mostly between 10 inches and infinity.

To make your object clearer you need to see the object more closely. It will help the object to become larger and this will help you to see the object larger. To increase the size of the image and to make it larger, you need to increase the angle from different angles.

How does light travel in each type of telescope?

In the refractor telescope, light directly enters near the objective lens. The objective lens is convex. This is the lens that converges the light. There is another point which is a focal point, the rays of light converge from this point.

This is the point where light again starts to diverge. There is another convex lens that is present in the eyepiece. This lens is used to converge the light. Moreover, it straightens out the light again to back it out. This magnifies the image and makes it more visible to focus on the image.

This is why the refractor has to have a long, and clear path to allow the light rays to bend. One of the downsides of this type of telescope is that the image appears upside down.

In the reflector telescope, the light enters the end of the telescope opposite the primary mirror. The mirror is concave here. In the secondary mirror, the light again converges through the concave mirror. This is similar to the convex lens.

There the ray of the light again converges at the focal point. They again start to diverge at this point. Here, again the convex lens in the eyepiece starts to converge and straighten it back out. As with the refractor, the image is still upside down. It appears as a virtual image beyond the telescope in the direction the person is looking.


There you have seen how does a telescope work. This is very important to note and take into account all the important points to make your telescope better for work. This is crucial to know about all the parts of the telescopes. This will help you to see that if the telescope is working correctly or not.

Make sure to check the aperture, the eyepiece, and lenses to clear the functioning of the telescope. If you are aware of these parts this will help you to see the objects and image more clearly. Make sure to focus on the diameter of the aperture this will help you to see the object larger and fainter.