What is a sun photometer and what does it measure?
A sun photometer is a type of light meter that measures the amount of sunlight. Most sun photometers measure the amount of sunlight for a narrow range of colors or wavelengths. All sun photometers should measure only the sunlight arriving directly from the sun and not the sunlight scattered from air molecules and aerosols. Therefore a sun photometer is pointed directly at the sun and the light is collected through a small apenure (hole or opening) that greatly restricts the amount of scattered sunlight that reaches the instrument’s detector(s).
