Advantages and Disadvantages

These are the advantages and disadvantages of the reflecting telescope. This is one persons opinion on what is an advantage and what is a disadvantage and therefore you may not agree.

Disadvantages:

*The mirrors used in reflecting telescopes are expensive and time consuming to make.

*The most advanced electronic light detection devices (CCD's) can only use 70% of the light they receive. That is 30% wasted.

*The mirror has to be extremely smooth. What may appear to be smooth may not be smooth to a particular wavelength of light.

*Like any optical telescope the atmosphere distorts the incoming light. You can see this effect when stars "twinkle". The moving atmosphere causes this illusion.

*A single large mirror is very heavy, and as such, requires expensive mounting to allow it to move freely. It is also affected by heat.

*The optical based nature of the reflecting telescope does not allow it to pick up radio signals from stars or other bodies in space.

Advantages:

* Early reflecting telescopes could be constructed much smaller than the refracting telescopes. This is because the refracting telescopes produced 'chromatic aberration' from the lenses splitting the light wave into its components. The increased length reduced this effect.

*Unlike a lens in a refracting telescope, the mirror can be supported from the back and sides. A lens can only be supported from the sides.

*Technology now allows the mirror of the telescope to change shape according to the movement of the atmosphere and the distortion this causes. This is known as adaptive optics, and can not be installed in refracting telescopes.

*Mirrors can also collect infra-red and ultraviolet light, unlike lenses which can only collect visible light.

*No chromatic aberration is produced by a mirror because it does not refract, or change the speed of, the light.

*Mirrors can be formed in many different ways, depending on the situation. They can be spinning liquid mirrors or solid glass mirror. New surface can be made to reflect light even more effectively.