astronomy chapter five

Card Set Information

astronomy chapter five
2012-04-06 14:33:27

Key terms and concepts- telescopes
Show Answers:

  1. electronmagnetic radiation
    changing electric and magnetic fields that travel through space at the speed of light and transfer energy from one place to another
  2. wavelength
    the distnace between successive peaks or throughs of a wave
  3. photon
    a quantum of electonmagnetic energy; carries an amount of energy that depends inversely on its wavelenth
  4. spectrum
    an array of electromagnetic radiation displayed in order of wavelenth
  5. nanometer
    a unit of distance equaling one-billionth of a meter: commonly used to measure the wavelength of light
  6. angstrom
    a unit of distance: commonly used to measure the wavelength of light
  7. atmosphere window
    wavelength region in which our atmosphere is transparent- at visual, infared, and radio wavelengths
  8. focal length (for the telescope)
    the distance from the lens to the point where it focuses parrallel rays (light coming from very great distances)
  9. primary lens/mirror
    the largest lens or mirror in a telescope
  10. refracting telescope
    a telescope that forms images by bending light with a lens
  11. reflecting telescope
    a telescope that uses a concave mirror to focus light into an image
  12. chromatic abberation
    a distrortion found in refracting telescopes because lenes focus different colours at slightly different distances. which means the miages are surrounded by colour fringes.
  13. achromatic lens
    a telescope lens composed of two lenses ground from two different kinds of glass and designed to bring two selected colours to the same focus and correct for chromatic abberation
  14. diffraction fringe
    Blurred fringe surrounding any image, caused by the wave properties of light. Because of this, no image detial smaller than the fringe can be seen
  15. spectrograph
    a device that seperates light by wavelengths to produce a spectrum

  16. grating
    a peice of material in which numerious microscopic parallel lins are scribed. light encountering a grafting is dispersed to form a spectrum
  17. cosmic rays
    subatomic particles, such as electrons and protons, traveling at nearly the speed of light.