Optical Telescopes

telescope repairsThe reflecting telescope uses a curved mirror to collect light. This main mirror, fixed to one end of a tube, concentrates the light onto a secondary mirror, which then reflects it into an eyepiece, which is fixed at right-angles to the main tube of the telescope. The object is then viewed by the observer.

The larger the telescope's mirror or lens, the fainter the object that it can view, and the greater the magnifying power you can use with it. Large mirrors are cheaper to make than lenses.

One of the largest reflecting telescopes in the world has a mirror some 10 metres in diameter.

The refractor was invented in 1608. In its simple form, it is a tube with a main lens at one end, and an eyepiece, with at least two lenses, at the other. The main lens collects and focuses light, and this light, and the image of the object that is being viewed, i.e. a planet, is formed in front of the eyepiece lens. The image is then magnified by the eyepiece. The refractor gives an upside-down image of the object being viewed.