Astronomical spectroscopy

Article By:

Massey, Philip National Optical Astronomy Observatories, Tucson, Arizona.

Prato, Lisa Lowell Observatory, Flagstaff, Arizona.

Aller, Lawrence H. Formerly, Department of Physics and Astronomy, University of California, Los Angeles, California.

Last reviewed:October 2019

DOI:https://doi.org/10.1036/1097-8542.057700

The use of spectroscopy (the analysis of light as a function of wavelength) as a tool for obtaining observational data on the chemical compositions, physical conditions, and radial velocities of astronomical objects. Astronomical applications of optical spectroscopy from ground-based observatories cover the electromagnetic spectrum from the near-ultraviolet [wavelengths around 0.3 micrometers (μm)] through the visible (0.4–0.7 μm) and into the near-infrared (2 μm). Space-based observatories, such as the Hubble Space Telescope and the Herschel Space Observatory, extend spectroscopic observations from the far-ultraviolet (0.1 μm) to the far-infrared (200 μm). Work at shorter wavelengths (x-ray and gamma-ray spectroscopy) and longer wavelengths (submillimeter and radio wavelengths) requires techniques other than those discussed here. See also: Gamma-ray astronomy; Hubble Space Telescope; Radio astronomy; Submillimeter astronomy; Ultraviolet astronomy; X-ray astronomy

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