AST-1001 Lecture Notes - Lecture 5: Altazimuth Mount, James Webb Space Telescope, Herschel Space Observatory
Document Summary
In astronomy, we cannot perform experiments with stars, galaxies, etc. The only way to investigate them is by analyzing the light (and other radiation) we observe from them. Not all radiation involves dangerous high-energy particles. The electric field and magnetic field are perpendicular. All electromagnetic waves travel at the speed of light (c = 3x10^8 m/s) One wavelength is the distance between repeating parts of a wave. Amplitude is the height of a wave. Frequency = 1/period (t) and t = 1/f. From lowest energy/longest wavelength to highest energy/shortest wavelength radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, x-rays, gamma rays. Wavelengths of light are measured in units of nanometers (nm) or angstroms (a) Visible light has wavelengths between 4000 a and 7000 a. Different colors of visible light correspond to different wavelengths. Light can also appear as particles, called photons. A photon has a specific energy , proportional to the frequency f.
