Spectroscopy Of all the information about astronomical objects, the vast majority comes from the spectroscopy of light.
Spectroscopy is the study of the component wavelenghts of light after they have been dispersed.
To split up the light, or disperse it, astronomers use a spectroscope, a spectrograph, or a spectrometer. All these instruments disperse the light so that it can be analyzed. Spectral Line Description Continuous Spectra take on different characteristics depending on the source of the light. This is known as a continuous spectrum. If you instead view the spectrum of a hot gas, such as hydrogen, you see something very different.