How do telescopes help us see distant objects?« Back to Questions List

Telescope was invented by Galileo to view distant objects. Any object at a large distance looks tiny than it actually is. A telescope helps view distant objects by magnifying them. 

Before going further into how telescopes magnify objects, let’s learn how our eye is able to view an object. When we see an object, light from the object enters our eye. These light rays travel through lens within our eyes and gets focused to a single point on the retina. An image of the object is now formed at the place where light was focused. There are photoreceptor cells that help translate the light rays into signals interpreted by our brains. So better the light got from the object, clearer is the object viewed. This simple logic is used in telescopes which bends, focuses and magnifies the light that falls on it.

Telescopes are either made with glass lenses or mirrors. The ones made of lenses are called refractor telescopes and those with mirrors are called reflector telescopes. Both these types work but in different ways to magnify the distant object being viewed.
Both lens and mirrors try to collect lots of light from the object being viewed. The amount of light they collect depends on the size of the mirror or the lens in both cases. If more light could be collected, they could be focused to one point resulting in a brighter image of the object. When the right combination of lenses is used, magnification becomes far better.

Telescopes are categorized into different types like optical telescopes, radio telescopes, space telescopes and many others, depending on the purpose for which they are used.

Giant telescopes under erection; Universe to reveal more

Eyes and vision : Basics ought to be known.