[ TERC VHS-1 Sun Photometer ] [ Manual TOC ]
A Sun photometer (also spelled Sunphotometer) is an instrument that measures the intensity of sunlight arriving directly from the Sun. Since it is designed to be pointed directly at the Sun, a Sun photometer measures only direct sunlight, not the diffuse light scattered from the sky, haze and clouds. Since haze blocks some direct sunlight, a Sun photometer is an ideal instrument for measuring haze.
Scientists have used Sun photometers of various kinds for more than a century. The modern generation of hand held Sun photometers was pioneered in the late 1950's by Frederick Volz [1], who has made important discoveries about the effects of natural and volcanic haze on the environment.
Although some Sun photometers respond to a wide range of colors or wavelengths of sunlight, most include special filters that admit only a very narrow band of wavelengths. These filters are expensive. They also have a limited life. While some filters may work well for a decade or more, others may last only a few years.