Telescopes
There are many different types of telescopes. The most commonly known type is the optical telescope however there are five other main ones:
Optical Telescopes:
These are the most commonly known telescopes and are we use them to look into space or to look onto Earth from space. Other planetary objects can also be viewed from an optical telescope. Things such as stars, galaxies, planetary nebula and thing that emit visible light are visible through it. There are also two types of optical telescopes: reflecting and refracting. Refracting telescopes use a glass lens to bend or refract light and bring it into focus. The lens is convex and this bends light at the edge of the lens to a greater angle than light coming through the centre, therefore all the rays converge to a focus. Whereas a reflecting telescope uses a curved mirror instead of a lens to collect the light. The mirror is concave and gets thicker towards the edges. The mirror focuses the incoming light and this increases the telescopes light sensitivity, so dimmer objects can be seen through it.
Infra-red Telescopes: |
Infra-red telescopes are used to detect a lower energy then visible light so are usually emitted by cooler objects. They are placed on high mountains to reduce the fuzziness from low lying water vapor. Through them you can see galaxies far away from us, cooler stars and planetary nebula emit infra-red light.
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