INSTRUMENTATION OPTICS & OPTICAL PHENOMENA A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site photometer AERONET sun photometer. Image courtesy The NASA Langley COVE Surface Validation Group An instrument for measuring the amount of light. Depending on the purpose, a variety of filters can be used to measure light of specific wavelengths. A photometer can also be used to measure ambient light, or only a narrow beam that comes directly from a source such as the Sun. In astronomy, a photometer instrument used to measure the brightness of stars or other celestial objects. A photoelectric photometer records the electric current generated when light from a source falls onto a light-sensitive surface, kicking of electrons, which are then amplified into a measurable current by a photomultiplier. An area photometer, or imaging photometer, on the other hand, measures simultaneously the light intensity at each point of an extended object such as a nebula or galaxy using CCD detectors or an infrared array. Related categories    • INSTRUMENTATION    • OPTICS AND OPTICAL PHENOMENA Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP