Reflecting Telescope

Types of reflecting telescopes

A reflecting telescope

  • Mirrors instead of lenss
  • Usually have two mirrors
    • Primary
    • Secondary
  • Configurations
    • Newtonian
    • Cassegrain
    • Nasmyth/Coudé
      • Commonly used as professional telescopes


  • No chromatic aberration
    • All wavelengths of light reflect off the mirror the same
  • Easily made to be big
  • Cheaper than refractors of the same size
  • Only one side of the objective needs to be perfect (reflecting vs. passing through)


  • Easy to get optics out of alignment
  • Optics need frequent cleaning
  • Two mirrors --> can produce diffraction effects
    • "Christmas star" effect