Astronomy Today


How is spectroscopy used in modern astronomy?

Devices called spectrographs are used in conjunction with telescopes and detectors to conduct spectroscopy of objects in the universe. Typically, a modern spectrograph takes light collected through a telescope, usually through a narrow aperture. The incoming light is collimated—made parallel—through a special lens. Then this col-244 limated light bounces through a prism or off a diffraction grating to separate the light into its component colors. The image of the separated light—the spectrum—is then recorded, either photographically or digitally, using a sensitive camera. Once recorded, the spectrum can be analyzed for whatever information it holds about the object that produced it.


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