Fundamental Quantities

• intensity, flux
• inverse square law
• specific intensity: illustrations here, here, here, and here; Plieades star cluster optical, infrared, X-ray
• energy density, pressure
• integrated quantities
• broadband filters: commonly used wavelength bands; a filter wheel
  • Dark Energy Survey g-band filter and transmission curves for CCD and system
  • LSST filter changer and transmission curves
transmission curves for the home team

Radiation Transfer

• conservation of surface brightness
• sources and sinks
• the mighty transfer equation

Scattering

• cross section
• mean free path
• optical depth