Coloring book pdf download TELESCOPES Worksheets Free - Coloring Book

TELESCOPES Worksheets Free


The telescope is an observatory device used by astronomers that receives and displays all kinds of radiation from space. It was invented by Hans Lippershey in 1608, and was first used by Galileo Galilei in 1609 to make sky observations.


The telescope structure consists of an objective, eyepiece and a tube that protects these lenses. There are two types of telescopes according to the lens type. If the light from space hits a mirror in the telescope and comes to the eye after passing through the prism, this type is called a reflective (mirrored) telescope. If the light from space passes directly through the lenses and reaches the eye, this type is called a refractive (lensed) telescope.

Lensed Telescopes:

They are types of telescopes in which light comes to the eyepiece by passing through the lens in a long tube. A large lens called a lens refracts the light rays coming from the distant object and collects them in a certain focus. The observer looks through a smaller lens called the eyepiece, which magnifies the image formed by the lens. Lensed telescopes are also called refractive telescopes because they work on the principle of refraction of light. The lenticular telescope remains important today because other instruments can be attached to it, allowing direct measurements of celestial bodies.


- Easy to use and reliable because of its simple design.

- Since it shows flat, you have the opportunity to look at the land and watch the landscape

- With large apertures, moon, planet and double star observations are excellent.

- Image quality is pretty good as there is no second mirror.

- Ideal for observing distant earth objects.

- Since it is an optical tube, air currents are minimized. For this reason, the image is prevented from being affected by air currents.

- Color correction is good with achromatic lenses, very good with apocramatic or fluorite lenses.

Mirror Telescopes:

In mirrored telescopes, light rays are collected and focused by reflection from a concave mirror. Such telescopes are also called reflective telescopes.


- Ideal for observing deep space objects.

- Since they have less optical aberrations, they give a very bright image.


A good astronomy telescope should be able to give a clear image and collect enough light to allow faint objects to be clearly seen. Lensed telescopes give a wider and clearer image as the lens diameter increases, and the zoom becomes larger as the focal length increases. In mirrored telescopes, on the other hand, the greater the area of ​​the objective lens or the mirror, the greater the light-gathering power. This allows you to get a clearer image.

With lens telescopes, you have the opportunity to watch both the land and the sky. But mirror telescopes are only used for the sky as they give an inverted image. In the sky, reflecting telescopes are more efficient. It allows you to get clearer, farther images.

The light-gathering power of the telescope and the magnification power are different. The magnification of the telescope is the ratio of the telescope focal length to the ocular focal length.


Forget Magnification Power! What matters is Clarity.

The most important feature of a telescope is not its magnification power, but its light-gathering capacity. The light-gathering capacity depends on the diameter (aperture) of your telescope's primary mirror or lens. The more light there is, the better you can see.

The magnification power can be easily changed with the parts we call ocular. The important thing is not to see a celestial body big, but to see it clearly.

How Big of a Telescope Do You Need?

With 60mm-70mm lens or 3" mirror: You can easily see the craters of the Moon, the rings of Saturn and the four bright moons of Jupiter.

With 80mm-90mm lens or 4.5",6" mirror : Shows more details on the moon and planets. Bright nebulae and star clusters can be observed.

8" and above: Dim clusters, nebulae, and galaxies can be seen from a dark region away from light pollution.

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