photoelectric photometer
An instrument for measuring the brightness of a star by means of the electric current produced when its light falls on a light-sensitive surface (the photoelectric effect). The light gathered by a ...
photoelectric magnitude
The brightness of a star or other object measured with a photoelectric photometer. This measurement requires correction for atmospheric extinction and comparison with at least one photometric ...
photometer
An instrument for measuring the brightness of stars or other objects. In its widest sense the term can include the human eye or the photographic plate. Conventionally, the term is confined to ...
visual magnitude
(mv) The apparent magnitude of a star as estimated by the human eye. The eye is capable of ranking stars in order of brightness and estimating equality between two stars, or a star and an artificial ...
spectrometer
A spectrograph in which the output spectrum is scanned by a photoelectric photometer to produce a record of how the intensity of a spectrum varies with wavelength. A modern example is the radial ...
