You can also lodge a telephone complaint while you are in Australia by ringing the Australian Consumer Affairs and Fair Trading Hotline 1300 552 263 (local call cost within Australia). The call will be automatically forwarded to the fair trading agency in the state or territory from which you are calling.
Circular paraboloid. A parabolic (or paraboloid or paraboloidal) reflector (or dish or mirror) is a reflective surface used to collect or project energy such as light, sound, or radio waves. Its shape is part of a circular paraboloid, that is, the surface generated by a parabola revolving around its axis. The parabolic reflector transforms an incoming plane wave traveling along the axis into a spherical wave converging toward the focus.
This illustration shows how light enters a reflector telescope. Optical telescopes allow us to see further; they are able to collect and focus more light from distant objects than our eyes can alone. This is achieved by refracting or reflecting the light using lenses or mirrors.