Telescopes page 4

What is a telescope?

A telescope magnifies the image that we as humans can see through the use of a magnifying glass (eyepiece) in combination with a lens. The stars themselves are not so much bigger because of their distance, but the number of stars, the brightness and the structure becomes clearer with the use of a telescope. Due to the construction of a telescope, the diameter of the lens plays the main role when we talk about the sharpness of the image. With a larger diameter, the telescope captures more light and you can therefore observe fainter stars better. The first telescopes date back to 1608 and were designed in the Netherlands.

Types of telescope

There are several telescopes on the market, each of which uses different techniques to enlarge the image. We've outlined three types.

• Refractor: With a refractor, the light is refracted by the convex lens at the front of the telescope. By changing the direction of the light, the image we see can be magnified many times over. These telescopes therefore fall into a higher price category, but do make it possible to observe the structures of planets closer to the earth. The first binoculars that appeared on the market already made use of this technique and it is still a widely used type of telescope.
• Reflector: Instead of using a lens, the reflector uses a concave mirror at the bottom of the viewing tube. As the name implies, the light is reflected from this mirror, causing the light rays to converge at a single point. The eyepiece is mounted on the outside of the telescope tube, the extra mirror that directs light to this point therefore also blocks some light. Another name for the reflector comes from inventor Isaac Newton, the Newton telescope.
• Catadioptric: A third type combines the different systems of other types of telescopes. The catadioptric viewer therefore uses both convex lenses and concave mirrors. Many inaccuracies of other systems can be corrected by this combination. We see the high quality reflected in the cost.

Eyepieces

The eyepiece is close to the point we look through with the eye. This part of the telescope consists of several lenses that make the image perfectly parallel again. By turning the focus knob, the eyepiece can move in or out, allowing us to focus the image. By changing the eyepiece, the magnification factor of the image can be changed. Too large a magnification can cause blurry images, but with a set of eyepieces , you can test different effects.

Stabilise the image

For observing celestial objects it is important that the telescope can be placed in a stable manner, so that no vibrations arise in the image. Many telescopes are heavy and can be provided with more stability using a tripod. The tripod is already included with some telescopes, but not in other cases. It is therefore advisable to purchase a Tripod .

Maintenance

With a telescope, you can view beautiful images of the universe. It can be annoying when there is a blur or a lot of dust on the lens. It is therefore important to store parts such as eyepieces in a dust-free case. A lens cloth, air pump or lens pen can offer a solution to the various options for keeping the lens clean.