Telescope Facts



  • Optical telescopes magnify distant objects by using lenses or mirrors to refract (bend) light rays so they focus (come together).
  • Other telescopes detect radio waves, X-rays (see X-rays), or other kinds of electromagnetic radiation.
  • Refracting telescopes are optical telescopes that use lenses to refract light rays.
  • Reflecting telescopes are optical telescopes that refract light rays by reflecting them off curved mirrors.
  • Because the light rays are folded, reflecting telescopes are shorter and fatter than refracting ones.
  • Most professional astronomers do not gaze at the stars directly, but pick up what the telescope shows with light sensors called CCDs.
  • Most early discoveries in astronomy were made with refracting telescopes.
  • Modern observatories use gigantic reflector dishes made up of hexagons of glass or coated metal.
  • Large telescope dishes are continually monitored and tweaked by computers to make sure that the reflector’s mirrored surface stays completely smooth.
  • The giant mosaic mirror of a huge telescope is at the Smithsonian Observatory, Arizona.