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.
Figure 5 illustrates a typical Cassegrain reflector. Some large telescopes of this kind do not have a hole in the primary mirror but use a small plane mirror in front of the primary to reflect the light outside the main tube and provide another place for observation.eflecting telescopes have a number of other advantages over refractors. They are not subject to chromatic aberration because reflected light does not disperse according to wavelength. Also, the telescope tube of a reflector is shorter than that of a refractor of the same diameter, which reduces the cost of the tube.