Reflectors

A reflector telescope uses a  two mirror system for collecting available night sky light. The concave primary mirror on the bottom of the telescope reflects light to a pinpoint. The second flat mirror set at 45 degree redirects the light creating a focal point towards the eyepiece. Color fringing aberration is eliminated as all wavelengths of light travel at the same speed as it gets reflected. This style of telescope is usually less costly than a refractor telescope, mirrors are less expensive to manufacture compared to lenses. Mirror re-alignment or collimation is required with reflector telescopes.