A spectrograph is an instrument used to measure properties of light over a wide range of the electromagnetic spectrum, from ultraviolet to infrared. The most common type of spectrograph uses a prism or diffraction grating to disperse the light into its component wavelengths (colors), which are then recorded on a photographic plate or detector.
The earliest spectrographs were developed in the 19th century for use in astronomy. These instruments were used to study the Sun and other stars, providing information about their chemical composition, temperature, and motion. Today, spectrographs are used in many different fields, including medicine, forensics, and environmental science.
How does a spectrograph work?
Light from a source enters the instrument through an aperture (a hole or slit). The light then passes through a dispersing element (a prism or grating), which splits it into its component wavelengths (colors). The individual colors are then focused onto a detector (usually a photographic plate or electronic sensor), which records them. By analyzing the resulting spectrum, scientists can learn about the properties of the original light source.