Chapter 6 - Light and Telescopes:

Key Terms:

  • Light Waves: Electromagnetic radiation that travels in waves

  • Wavelength: Distance between two peaks of a wave

  • Frequency: Number of wave cycles per second

  • Light as Particles: Photons, packets of energy that make up light

  • Atmospheric Windows: Wavelength ranges where Earth's atmosphere is transparent

  • Refracting Telescope: Uses lenses to bend light

  • Reflecting Telescope: Uses mirrors to reflect and focus light

  • Chromatic Aberration: Dispersion of light into colors

  • Light Gathering Power: Ability to collect light

  • Resolving Power: Ability to distinguish fine details

  • Seeing: Atmospheric conditions affecting telescope performance

  • Adaptive Optics: Technology to reduce effects of atmospheric distortion

  • Resolution: Ability to distinguish two separate points

  • Interferometry: Combining signals from multiple telescopes

  • Radio Interferometer: Array of radio telescopes working together

Equations:

  1. Speed of Light

    1. λv = c

      λ = wavelength, v = frequency, c = speed of light: 3×10^8

  2. Light Gathering Power

    1. A = π(D/2)²

      D = diameter

  3. Angular Resolution (Alpha Min)

    1. α [arcsec] = 1.22(λ/D)

      α = minimum sized structure that may be resolved by a telescope (want to be small as possible, units of radians), λ = wavelength of observation, D = diameter of telescope