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.
Porro prism A combination prism consisting of two 90Âº totally reflecting prisms arranged at right angles to each other. It is used in optical systems, such as binoculars to invert the image and provide a shorter displacement. It is the most common erecting prism.