Describe the technology needed to measure astronomical spectra

Astrophysics > 3. Spectroscopy >

Describe the technology needed to measure astronomical spectra

  • Astronomical Spectra: Spectra produced by an astronomical object.
  • Stellar Spectroscopy: The examination of stars in order to learn more about their nature, including composition, surface temperature, velocity and density.
  • Astronomical spectra can be viewed using a spectroscope, or recorded and measured using a spectrograph, mounted at the focus of a telescope.
  • Spectroscope: Also known as a spectrometer, any of a range of devices used to disperse light into a spectrum in order to measure it.
  • A spectroscope consists of several main parts:
    • A collomator uses a slit and one or more mirrors or lenses to produce a parallel beam of light.
    • A dispersive element splits the beam into its wavelengths, consisting of either a prism or a diffraction grating.
    • A device the view the split wavelengths.
  • Spectrograph: An instrument consisting of a spectroscope and related equipment used to obtain a visual record of spectra.
  • Spectrographs can obtain a record using:
    • Photographic plates or film.
    • Electronic image device.
  • The record produced by a spectrograph is known as a spectrogram.