Introduces the major conventions and terms needed to understand planetary photometry. Included are the definitions and uses of the major coordinate systems, definitions of time scales and their use in planetary work, major terms used in planetary photometry - such as irradiance and radiance - and their interrelationships, the different types of magnitudes used by planentary sciences, the origin and overview of photometric systems such as the UBVRI system, and the standard stars and scales that tie these systems together.